D. Maria collects postcards. The table gives the
number of each type of postcard she has in her
collection. Use the data to write each ratio in
three different ways.
A. U.S. Landmarks to European Landmarks:

Answers

Answer 1

Answer: A. U.S. Landmarks to European Landmarks

Maria has 25 U.S. landmark postcards and 20 European landmark postcards. The ratio of U.S. landmarks to European landmarks can be written as 25:20 or as 25/20.

Alternatively, we can express the ratio as a fraction. If we divide the number of U.S. landmark postcards by the total number of U.S. and European landmark postcards, we get 25/(25+20)=25/45

The last way we can express the ratio as a decimal. By dividing the number of U.S. landmark postcards by the total number of U.S. and European landmark postcards, we can find that the ratio of U.S. landmarks to European landmarks is 25/45 =0.555 or 55.5%

Step-by-step explanation:


Related Questions


What’s the answer ?
Solve |2x - 3| ≥7

Answers

Answer:

x ≤ −2 or x ≥ 5

Step-by-step explanation:

Isolate the variable by dividing each side by factors that don't contain the variable.

Evaluate m - 16 when m = 30

Answers

[tex]m-16[/tex] when m is 30

Substitute for m with given value:

[tex](30)-16[/tex]

[tex]=\fbox{14}[/tex]

Answer:

Step-by-step explanation:

a.we can get the equation is m-16 = 30-16=10+20-10-6=10-6+20-10=4+10=14

answer is 14

PLEASE HELP FRACTION S EASY!! A construction worker is making concrete by mixing sand, gravel, and cement in water. For each pound of sand, he uses pounds of gravel. For each pound of gravel, he uses pound of cement. He is making enough concrete that he needs to use 3 pounds of sand.
How many pounds of cement does he use?

Answers

The pound of cement used based on the information will be C. 2 pounds.

How to illustrate the fraction?

A fraction simply means a piece of a whole. In this situation, the number is represented as a quotient such that the numerator and denominator are split. In this situation, in a simple fraction, the numerator as well as the denominator are both integers.

In this case, for each pound of sand, he uses 1 2/3 pounds of gravel and for each pound of gravel, he uses 2/5 pound of cement.

The pound of cement used will be:

Gravel = 1 2/3 × 3

= 5 pounds

Cement used will be:

= 2/5 × 5.

= 2 pounds.

Learn more about fractions on:

brainly.com/question/78672

#SPJ1

Mary bought 5 pounds of grapes for $19. Mark bought 4 pounds of grapes for $16. Complete the statement comparing Mary's unit rate with Mark's unit rate.

Answers

Mary paid $3.80 per pound and Mark paid $4.00 per pound.

19 ÷ 5 = 3.80

16 ÷ 4 = 4

Mary's unit rate is less than Mark's unit rate.

How to calculate expression?

To compare the unit rate of Mary and Mark, we need to find how much each of them paid per pound of grapes.

Mary paid $19 for 5 pounds of grapes, so her unit rate can be calculated as:

The unit rate of Mary = Total cost of grapes / Total amount of grapes purchased

= $19 / 5 pounds

= $3.80 per pound

Mark paid $16 for 4 pounds of grapes, so his unit rate can be calculated as:

The unit rate of Mark = Total cost of grapes / Total amount of grapes purchased

= $16 / 4 pounds

= $4.00 per pound

Comparing the unit rate of Mary and Mark, we can see that Mary paid less per pound of grapes than Mark did.

To know more about an expression follow

https://brainly.com/question/29286007

#SPJ2

4. Torrie has $430 and Sonia has $760. John has the same number of dollars more than Torrie as he has less than Sonia. How much money does John have?​

Answers

To solve this problem, we can set up the following equation:

Torrie + John = Sonia - John

This equation represents the fact that John has the same number of dollars more than Torrie as he has less than Sonia. We can then substitute the given values for Torrie, Sonia, and John to solve for John:

430 + John = 760 - John

Combining like terms, we get:

2 * John = 330

Dividing both sides of the equation by 2, we get:

John = 165

Thus, John has $165.

Which of the following is the correct equation for the trend line in the scatter plot?

Answers

The equation of the trend line will be : Y = (1/4)x - 1.

What is trend line in scatter plots?A trend line is a straight line that best represents the points on a scatterplot. The trend line may go through some points but need not go through them all.

Given is a scatter plot a shown in the image.

The general equation of a straight line is -

y = mx + c

{m} - slope

{c} - intercept along the y - axis

We can find the slope as follows. The line passes through the points -

(4, 0) and (0, - 1). We can write -

m = (- 1 - 0)/(0 - 4)

m = - 1/-4

m = 1/4

and

[c] = - 1

So the equation of the trend line will be -

Y = (1/4)x - 1

Therefore, the equation of the trend line will be : Y = (1/4)x - 1.

To solve more questions on correlation, visit the link below -

https://brainly.com/question/28898177

#SPJ1

The volume of this sphere is 4500m³.
Find the length of the radius, r.

Answers

Answer:

[tex]r=\frac{15\sqrt[3]{\pi ^2} }{\pi }[/tex]  meters

[tex]r=10.24[/tex]  meters

Step-by-step explanation:

Here is the equation for the volume of a sphere

[tex]V=\frac{4}{3} \pi r^{3}[/tex]

Lets solve for [tex]r[/tex].

Multiply both sides of the equation by [tex]\frac{1}{\frac{4}{3}\pi}[/tex].

[tex]\frac{1}{\frac{4}{3}\pi}(\frac{4}{3}*(\pi r^3))=\frac{1}{\frac{4}{3}\pi}V[/tex]

Simplify the left side.

Combine [tex]\frac{4}{3}[/tex] and [tex]\pi[/tex].

[tex]\frac{1}{\frac{4\pi }{3}}(\frac{4}{3}*(\pi r^3))=\frac{1}{\frac{4}{3}\pi}V[/tex]

Multiply the numerator by the reciprocal of the denominator.

[tex]\frac{3}{4\pi } (\frac{4}{3}*(\pi r^3))=\frac{1}{\frac{4}{3}\pi}V[/tex]

Cancel the common factor of [tex]\pi[/tex] by factoring it out of the first term.

[tex]\frac{3}{4} (\frac{4}{3}*r^3)=\frac{1}{\frac{4}{3}\pi}V[/tex]

Combine [tex]\frac{4}{3}[/tex] and [tex]r^3[/tex].

[tex]\frac{3}{4}*\frac{4r^3}{3}=\frac{1}{\frac{4}{3}\pi}V[/tex]

Multiply the numerators on the left side of the equation. Then multiply the denominators.

[tex]\frac{12r^3}{4*3}=\frac{1}{\frac{4}{3}\pi}V[/tex]

[tex]\frac{12r^3}{12}=\frac{1}{\frac{4}{3}\pi}V[/tex]

Cancel the common factor of 12.

[tex]r^3=\frac{1}{\frac{4}{3}\pi}V[/tex]

Simplify the right side.

Combine [tex]\frac{4}{3}[/tex] and [tex]\pi[/tex].

[tex]r^3=\frac{1}{\frac{4\pi }{3}}V[/tex]

Multiply the numerator by the reciprocal of the denominator.

[tex]r^3=\frac{3V}{4\pi }[/tex]

Take the cube root of both sides of the equation to eliminate the exponent on the left side.

[tex]r=\sqrt[3]{\frac{3V}{4\pi } }[/tex]

Now we have an equation to find the radius.

Substituting our number for volume gives us

[tex]r=\sqrt[3]{\frac{3*4500}{4\pi } }[/tex]

Enter this into a calculator

[tex]\sqrt[3]{\frac{3*4500}{4\pi } }[/tex]

You can leave the answer in simplest radical form or as a decimal.

[tex]r=\frac{15\sqrt[3]{\pi ^2} }{\pi }[/tex]

[tex]r=10.24[/tex]

A rating/review would be much appreciated. Hope this helps!

Please help me asap

Answers

On solving the provided question, we cans ay that By unitary method, the amount to be removed = original - shortened = 3/9 - 2/9 = 1/9

What is unitary method ?

The unit technique is an approach to problem-solving that involves first determining the value of a single unit, then multiplying that value to determine the required value. The unit method, to put it simply, is used to extract a single unit value from a supplied multiple. For instance, 40 pens would cost 400 rupees, or the price of one pen. The process for doing this may be standardized. a single country. anything that has an identity element. (mathematics, algebra) (Linear algebra, mathematical analysis, mathematics of matrices or operators) Its adjoint and reciprocal are equivalent.

By unitary method,

original length of pipe = 3/9 inch

shortened length of pipe = 2/9

so, the amount to be removed = original - shortened = 3/9 - 2/9 = 1/9

To know more about unitary method  visit:

https://brainly.com/question/28276953

#SPJ1

72 ounces and 6 steaks = what rate and unit rate

Answers

the answer is 9oz/ per steak

Can someone pls tell me how to do this?

Simplify (5y)³

Answers

Answer: 125y³

To rise a product to a power, rise each factor to that power:

(5y)³ = 5³y³ = 125y³

Maria Brought 3 cakes of the same size for her birthday. half of one cake was left and one-third of qther. how much cake was left over altogether?​

Answers

Answer:

7/12 (seven over twelve)

Step-by-step explanation:

1/3 -1/4 =4/12- 3/12=1/12

1/2+1/12=6/12+1/12=7/12

so the answer is 7/12

hopefully this helps

PLEASE HELP

All numbers less than 17 and greater than or equal to -8

Answers

Answer: C

Step-by-step explanation: it says that it's smaller or equal to x and x is smaller than 17

Answer: 17>n ≥-8

1. All number less than 17 can write as n< 17

2. All numbers greater than or equal to -8 can written as n ≥ -8.

3. Flip n<17 so n can be in the middle of the inequality.

4. Combined it would be 17>n ≥-8

Select three correct interpretations about the graph of r(t).
T
A. The average mortgage rate increased continuously
between 2003 and 2005.
B. The average mortgage rate fell to a relative minimum
between 2002 and 2003.
C. Based on the y-intercept, the average mortgage rate in
2010 was about 7.7%.
X
D. Based on the absolute maximum, the average
mortgage rate was highest between 2006 and 2007.
E. An appropriate domain for this function is 0≤t≤10

Answers

Answer: The correct interpretations about the graph of r(t) are B, D, and E.

Interpretation B is correct because the graph shows that the average mortgage rate fell to a relative minimum between 2002 and 2003.

Interpretation D is correct because the graph shows that the average mortgage rate was highest between 2006 and 2007, based on the absolute maximum.

Interpretation E is correct because an appropriate domain for this function would be 0≤t≤10, as t represents time and the graph shows data for the period between 2002 and 2010.

Interpretation A is not correct because the graph does not show that the average mortgage rate increased continuously between 2003 and 2005.

Interpretation C is not correct because the y-intercept does not represent the average mortgage rate in 2010. The y-intercept represents the value of the function when t = 0, which does not correspond to any time in the given data.

Step-by-step explanation:

The table, the equation, and the graph show the rates at which three different students read in words per
minute. Which student reads faster?

Answers

The student that has the highest reading rate is Student C who has the highest rate of change of the number of words read of 158 words per minute.

What is the rate of change of a function?

The rate of change of a function is the rate at which the output value changes per unit change in the input value.

The possible data and table obtained from a similar question on the website are presented as follows;

Student A

Number of minutes;         [tex]{}[/tex]1              2             3              4

Number of words read; 150        [tex]{}[/tex]300          450          600

Student B

y = 158·x

Where;

x = The time duration in minutes

y = The number of words read by the student

Student C

The points on the graph representing the reading rate of student C are; (2, 280), (3, 420), (5, 700)

The first difference of the number of words read by Student 1 is constant, indicating that the relationship is a linear relationship, with the reading rate obtained by the rate of change of the number of words read as follows;

Reading rate for Student A = (300 - 150)/(2 - 1) = 150

The reading rate for Student A is 150 words per minute

The equation for the reading rate of Student B; y = 158·x, indicates that Student B reads 158 words per minute

The of the straight ling graph for the reading rate of Student C is found as follows;

Slope = (420 - 280)/(3 - 2) = 140

The slope indicates that the number of words read by Student C increases by 140 words every minute, therefore, the reading rate for Student C is 140 words per minute

The student that reads fastest is therefore, Student C who has a reading reading rate of 158 words per minute

Learn more about the slope of the graph of a function here: https://brainly.com/question/13434264

#SPJ1

Autumn received $150 for her birthday this year.
This was $10 less than half the amount she
received last year. How much money did
Autumn receive for her birthday last year?
Write an equation to model this situation.
Let x = the amount of money Autumn received
last year

Answers

(150/2)-10=x
Autumn received $65 last year

A store is having a sale on almonds and jelly beans. For 5 pounds of almonds and 2 pounds of jelly beans, the total cost is $12. For 3 pounds of almonds and 8 pounds of jelly beans, the total cost is $31. Find the cost for each pound of almonds and each pound of jelly beans.

Answers

To find the cost of each pound of almonds, we need to find the difference in the cost of the almonds between the two purchases and divide it by the difference in the number of pounds of almonds. In this case, the difference in the cost of the almonds is $31 - $12 = $19 and the difference in the number of pounds of almonds is 3 - 5 = -2 pounds. Dividing the difference in the cost by the difference in the number of pounds gives us $19/-2 = $-9.50 per pound. This means that the cost of each pound of almonds is $-9.50.

To find the cost of each pound of jelly beans, we can use a similar process. In this case, the difference in the cost of the jelly beans is $31 - $12 = $19 and the difference in the number of pounds of jelly beans is 8 - 2 = 6 pounds. Dividing the difference in the cost by the difference in the number of pounds gives us $19/6 = $3.17 per pound. This means that the cost of each pound of jelly beans is $3.17.

Find the slope of the line passing through each of the following pairs of points. (–7, 1) (7, 8)

Answers

Use the equation Y2 - Y1/ X2- X1 = 7/14.

Answer:

1/2

Step-by-step explanation:

Slope(m)

= (y2 - y1)/(x2 - x1)

= (8 - 1)/(7+7)

= 7/14

= 1/2

Tara is painting her room she brought paint that takes 3 gallons to cover an area of 75 square feet how many gallons of paint will tara need to paint 375 square feet of her room

Answers

Tara will need gallons of paint

If you work for an airline need to sit a passenger every 30 seconds. If the doors open at 9:35 am, what time does the last passenger sit if there are 110?

Answers

The answer i think is 10:30 am because you just have to multiply the number of seconds with people youll get 3,300 seconds divide that by the number of seconds are in a minute (60 seconds) then you’ll get 55 mins then its adding from there

Answer: 10:30 am

Step-by-step explanation: If you need to seat a passenger every 30 seconds, (half of a minute, which is 60 seconds), for every minute, 2 passengers will be seated. So, if you seat 2 passengers for a min each until you have seated 110 people, you will have taken up 55 minutes in total. (110 divided by 2 passengers a min). And finally, 55 minutes past 9:35 am would be 10:30 am. Hope this helps!

Draw a number line to show 2/8 and 4/16 are equivalent.

Answers

Step-by-step explanation:

think of it as a ruler the small dashes represents the 16ths and the big dashes represents the 4ths. They are on the same line therefore they are equal.

Lucas hosted a New Year's dinner for his employees.
The total bill was $1,011.50. He left the server a 20%
tip. How much money did Lucas tip the server?
Round your answer to the nearest hundredth.

Answers

Answer:

  $202.30

Step-by-step explanation:

You want to know the value of a 20% tip on a bill of $1011.50.

Tip

The tip amount can be found by multiplying the bill amount by the tip percentage:

  20% · $1011.50 = $202.30

Lucas tipped the server $202.30.

__

Additional comment

You know that 10% of the amount can be found by moving the decimal point one place: $101.15.

20% of the amount will be double this value: $202.30. You can do this math mentally.

Please help im timed on this

Answers

The slope of the line is 1.25 and the value of x is 12.

What is slope of a line?

A line's slope is defined as the ratio of the change in y coordinate to the change in x coordinate. A line's slope provides information on the steepness and direction of the line. the angle at which two straight lines intersect.

Given that:

rise =10

run = 8

The slope is determined by the following formula:

Slope = Rise / Run

[tex]Slope = \frac{10}{8} = 1.25[/tex] .

The slope of a line equation is given by:

[tex]y_2 - y_1 = m (x_2-x_1)[/tex]

Here, m is the slope of the equation.

Substitute the value of [tex]m= \frac{10}{8}, y_2=21 , y1= 6, x_2 =x, x_1= 0[/tex] in the equation.

[tex]21-6 = \frac{10}{8}(x-0)\\ \\15= \frac{10}{8} (x)\\\\(15)(8) = 10x\\\\120=10x\\\\x=12[/tex]

Hence the value of x is 12.

Learn more about slope here:

https://brainly.com/question/3605446

#SPJ1

Answer:

The slope of the line is 1.25 and the value of x is 12.

Step-by-step explanation:

The sum of the age of a girl and her brother is 34. The girl is 8 years older than her heather, how old is her brother​

Answers

Answer:

26

Step-by-step explanation:

if she is 8 years older, then is just 34-8 which is 26

please help me thank you so much

Answers

1) E = 1/2F - E has half of what F has

2) 1/2F - half of what F has

its 9/16 close to 0, 1/2 or 1 explain

Answers

Answer: It's closer to 1/2

Step-by-step explanation: It's closer to 1/2 and here's why:

So, 1/2 (exact) is 8/16

0 = 0

1 = 16/16

Since 9/16 is the closest to 8/16 or around 1/2 in this case, it'd be about 1/2. I hope this helps!

Find the equation of a line that passes through the points (2,7) and (4,6). Leave your answer in the form y = mx + c​

Answers

[tex](\stackrel{x_1}{2}~,~\stackrel{y_1}{7})\qquad (\stackrel{x_2}{4}~,~\stackrel{y_2}{6}) ~\hfill \stackrel{slope}{m}\implies \cfrac{\stackrel{\textit{\large rise}} {\stackrel{y_2}{6}-\stackrel{y1}{7}}}{\underset{\textit{\large run}} {\underset{x_2}{4}-\underset{x_1}{2}}} \implies \cfrac{ -1 }{ 2 } \implies - \cfrac{ 1 }{ 2 }[/tex]

[tex]\begin{array}{|c|ll} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-\stackrel{y_1}{7}=\stackrel{m}{- \cfrac{ 1 }{ 2 }}(x-\stackrel{x_1}{2}) \\\\\\ y-7=- \cfrac{ 1 }{ 2 }x+1\implies {\Large \begin{array}{llll} y=- \cfrac{ 1 }{ 2 }x+8 \end{array}}[/tex]

A machinist must cut 12 strips of metal that are each 3 ft 4 7/8 in. long. What is the total length needed in inches?

Answers

The total length needed in inches will be 490.5 inches.

How to calculate the fraction?

A fraction simply means a piece of a whole. In this situation, the number is represented as a quotient such that the numerator and denominator are split. In this situation, in a simple fraction, the numerator as well as the denominator are both integers.

Since the machinist must cut 12 strips of metal that are each 3 ft 4 7/8 in. long  The total length needed in inches will be:

= (3 ft 4 7/8 inch × 12)

Note that 1 feet = 12 inches

= (12 × 3) + (4 7/8) × 12

= (36 + 4.875) × 12

= 490.5 inches

Learn more about fractions on:

brainly.com/question/78672

#SPJ1

What is the equation of the line that passes through the point (-4,-4) and has a
slope of -3/4?

Answers

[tex](\stackrel{x_1}{-4}~,~\stackrel{y_1}{-4})\hspace{10em} \stackrel{slope}{m} ~=~ - \cfrac{3}{4} \\\\\\ \begin{array}{|c|ll} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-\stackrel{y_1}{(-4)}=\stackrel{m}{- \cfrac{3}{4}}(x-\stackrel{x_1}{(-4)}) \implies y +4= -\cfrac{3}{4} (x +4) \\\\\\ y+4=-\cfrac{3}{4}x-3\implies {\Large \begin{array}{llll} y=-\cfrac{3}{4}x-7 \end{array}}[/tex]

Answer:

y = -3/4x - 7

Step-by-step explanation:

Given: slope = m = -3/4

Plug this value into the standard slope-intercept equation of y = mx + b.

y = -3/4x + b

To find b, we want to plug in a value that we know is on this line: in this case, point (-4, -4). Plug in the x and y values into the x and y of the standard equation.

-4 = -3/4(-4) + b

To find b, multiply the slope and the input of x(-4)

-4 = 3 + b

Now, subtract 3 from both sides to isolate b.

-7 = b

Plug this into your standard equation.

y = -3/4x - 7

This is your equation.

Learn more with another example:

https://brainly.com/question/27643891

How do logarithmic functions model real-world problems and their solutions? Give a specific example and explain.

Answers

The process of logarithmic functions in real-worlds problems is given below.

And an example of an application of logarithmic function is given.

What is Logarithmic?

The inverse of exponentiation is the logarithm. This indicates that the exponent to which b must be raised in order to obtain a number x is the logarithm of x to the base b.

We know,

logarithmic function and exponential function are inverse of each other.

So, whenever we solve the exponential function,

we use the help of logarithmic functions.

To compute the number with bigger exponents,

we use the logarithms.

Because it reduces the size of the numbers.

Let the bacteria is growing exponentially,

b = 2ⁿ.

We know that the bacteria grows every hour.

We want to find time.

Here, we will use the inverse function to the exponential function.

How long will it take them to get 1000 bacteria?

1000 = 2ⁿ

Taking log on both sides,

log(1000) = n log2

n = log(1000)/log(2)

n = 9.96

n ≈ 10 hours.

Therefore, an application of logarithmic function is given above.

To learn more about the logarithms;

brainly.com/question/28346542

#SPJ1

Determine the value of x.

A) 2√3 B) 6√3 C) 12 D) 12√3

Answers

The required measure of the value of x is given as 2√3. Option A is correct.

What are trigonometric equations?

These are the equation that contains trigonometric operators such as sin, cos.. etc. In algebraic operations.

here,
Consider the given triangle,

perpendicular = 6
base = x

Applying trigonometric operation,
tan30 = perpendicular/base
tan30 = 6/ x
x = 6/√3
x = 2√3

Thus, the required measure of the value of x is given as 2√3. Option A is correct.

Learn more about trigonometry equations here:

brainly.com/question/22624805

#SPJ1

Other Questions
if crystals room measures 10.5 ft long and 7 feet wide and 9 feet tall how much paint will be needed to paint her bedroom Given A(0, a) and B(b, 0) , find coordinates of C so that the orthocenter of triangle ABC lies on the triangle. A salesperson earns a weekly salary of $150 plus a 15% commission of her total sales. Her total sales for the week is $15,000. How much does she earn for the week If you have a set of holiday lights that is on a series circuit, predict what would happen if the series circuit were cut off in the middle. Infer how this would differ from what would happen with a parallel circuit. Through his work, Humboldt challenged European notions about a continent that to some degree had been shaped by people who had never set foot in South America. What does this sentence imply? Two alien spaceships start traveling toward each other from space stations that are 710,000 km apart. The first spaceship started an hour before the second spaceship and is traveling at 110,000 km/hr. In how many hours will the two spaceships meet if the second spaceship is traveling at 90,000 km/hr?The spaceship will meet in how many hours? How can you identify and write equivalent expressions? A nurse is teaching the partner of a client who had a stroke about manifestations of dysphagia. Which of the following statements by the client's partner indicates the need for further teaching?A. "I will monitor my husband for coughing while he's eating."B. "I will monitor for a change in my husband's voice after he swallows."C. "I will monitor my husband for tilting his head forward when he swallows."D. "I will monitor my husband for pocketing food in his mouth. A technician performs a medication reconciliation in order to: Select one: Consult the patient Prevent drug errors Diagnose the condition Administer the medication What are the main features of Nazi ideology? What determines the cost of life insurance? Select all ratios equivalent to 16:12 A. 12:9 B. 4:24 C. 48:36 Find the subject in the following sentence? Mr. French has been teaching students for many years.A.Students B.Years C.has been teaching D.Mr.French 4) Add commas, colons, and semicolons to the following sentence. Use exact spelling and correct spacing. "Don't forget to take the trash out" Mom reminded us. The spring in a scale stretches 1 centimeter when a 5-newton object hangs from it. How much does an object weigh if it stretches the spring 2 centimeters what weather system might be occuring if austrailia is experienceing droughts and parts of south america are flooded . Marissa is painting one of her bedroom walls. She marks off of the wall. Then she divides the marked section into 3 equal parts and paints one part blue. What fraction of the whole wall is blue? Explain briefly why it's helpful to choose a chord progression before developing the harmony Why was the Munich Agreement so important? What are the impacts of nicotine and tobacco on the human body?