Answer:
1.The period during which a heart chamber is contracting is called systole.
2. The period during which a heart chamber is relaxing is called diastole.
3. During ventricular contraction, the AV valves (tricuspid and mitral valves) are closed.
4. During ventricular relaxation, the AV valves are open.
5. The pulmonary and aortic valves open when the pressure in the ventricles exceeds the pressure in the pulmonary trunk and aorta.
6. The first sound of a cardiac cycle occurs when the atrioventricular valves are closing.
7. The second sound of a cardiac cycle occurs when the semilunar valves are closing.
Explanation:
We can divide the heart cycle into two parts the systole and the diastole. The systole happens when the heart walls contract, and the diastole when these relax.
The relaxation and contraction allow the flow of blood into the different heart chambers.
During diastole, blood flows to the right atrium from the vena cavae superior and inferior, and the coronary veins and to the left atrium from the pulmonary veins. The blood accumulated in the atriums causes the AV valves to open, and blood flows to the ventricles. In this part, the atrium pressure exceeds the ventricular pressure allowing the blood's flow. When the atriums contract, the remaining blood that was in them, goes to the ventricles. Throughout all this process, the pulmonary and aortic valve is closed due to a pressure difference.
During ventricular systole, there are two phases. First, the ventricles contracts themselves, and the ventricular pressure increases, being higher than the atrium pressure. As a consequence, the AV valves close. During this first phase of contraction, there is not enough pressure to open the pulmonary and aortic valves. In the second phase, the ventricles completely contract themselves, the ventricular blood pressure increases. It becomes higher than the pressure in the aortic and pulmonary valves. As a consequence, the blood pushes the valves open, and blood goes out of the heart. Then, the difference in pressure between the ventricles and the pulmonary trunk and aorta causes the valves in these areas to close.
The first sound that we listen to is the S1 and is during the ventricular contraction that closes the atrioventricular valves. The second sound is the S2, and it happens when the semilunar valves close, also knowns as aortic and pulmonary valves. S2 occurs during diastole once that the blood is out of the ventricle and the contraction has finished.
Help please, will give points!
does photosynthesis remove take or use co2 from atmosphere
Answer:
Photosynthesis removes carbon dioxide naturally — and trees are especially good at storing carbon removed from the atmosphere by photosynthesis.
Explanation:
This is full explanation :)
Answer:
use and take?
Explanation:
they take in carbon dioxide and make it into glucose
Humans decide which varations are favorable or desired.
A. Artificial Aelection
B. natural selection
C. both
Answer:
Artificial selection
Explanation:
Artificial selection is the identification by humans of desirable traits in plants and animals, and the steps taken to enhance and perpetuate those traits in future generations.
How many atriums does the heart contain?
There are 2 atriums, The left atrium and the right atrium
The data showed that recently the alligator population has decreased. How could the decrease in the alligator
population affect the other populations? Be sure to explain whether the gar population, the diving duck population, and
the crab population will change, and why.
Answer:
the gar population will increase, the diving duck will decrease slightly and the crab population will decrease
Explanation:
Since the alligator population will decrease, the gar population won't have anything to limit their population, so they will increase fast. The crab population will decrease fast as there are more gars to eat them. The duck population will decrease slightly as the gar is eating more crabs then the duck
Which of the following is the correct sequence of events in Protein Synthesis?
A. mRNA strand is formed, mRNA is processed, polypeptide chain is formed, protein is modified
B. Polypeptide is formed, mRNA is processed, polypeptide chain is formed, mRNA is modified
C. mRNA strand is formed, polypeptide chain is formed, mRNA is processed, protein is modified
D. Polypeptide chain is formed, protein is modified, mRNA strand is formed, mRNA is processed
Answer: A
Explanation:
It can't be B or D because to get the polypeptide chain, we need the mNRA first to go through the ribosome. It's not C because after the mRNA is generated in the nucleus, it undergoes some modifications like splicing and the addition of the 5' cap and 3' tail.
The answer to the question is option A which is mRNA strand is formed, mRNA is processed, polypeptide chain is formed, protein is modified.
What is Translation?
In its most basic form, expressing a gene implies producing its matching protein, and this multi-step process comprises two primary phases. The information in DNA is converted to a messenger RNA (mRNA) molecule in the first phase, which is known as transcription.
During transcription, the DNA of a gene acts as a template for complementary base pairing, and an enzyme called RNA polymerase II catalyses the creation of a pre-mRNA molecule, which is subsequently processed to form mature mRNA. The mRNA that results is a single stranded copy of the gene that must then be translated into a protein molecule.
The genetic coding is used to "read" the mRNA, which connects the DNA sequence to the amino acid sequence in proteins, during translation, the second key step in gene expression.
Each codon in mRNA is made up of three nucleotides and represents a different amino acid.
As a result, The mRNA sequence serves as a template for constructing the chain of amino acids that comprise a protein in the correct order.
So we can conclude that first mRNA strand is formed then mRNA is processed, then polypeptide chain is formed and protein is modified.
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What is Nondisjunction
and when does it happen?
Answer:
I is when two or more chromosomes fail to separate, which makes daughter cells with abnormal amounts of chromosomes
Explanation:
Your welcome.
help with this plz!!
Answer:
i think it might Be B. but im not 100% sure but it seems to be the only logical one
Explanation:
what kind of flower is this?
Answer: could be Trifolium repens Aka the white clover
Explanation:
3:Briefly describe in a paragraph your learning Online experience as a Science students.
Answer:
i also don't know i am in 9 hahahaha
Answer:
I honestly love it! Not only does online school give me more freedom to do my daily activities such as sports and cooking but it also reduces my in-person learning stress. With science specifically, I can create visual representations of the lesson/subject matter to help me better understand the question or item being taught. It can also be more difficult at times because you don't have a teacher that you can raise your hand for and get an immediate answer or help with your question as you would in a typical brick-and-mortar/physical school classroom.
Hope this helps and please leave me brainliest!Which population will likely decrease in size in the near future?
Question
If a population's growth rate decreases as the population size approaches
carrying capacity, the population's growth follows a(n) ______ model.
exponential growth
density-dependent growth
geometric growth
logistic growth
2 of 20
Determine the density of a rabbit population, you would need to know the population count of the rabbits and ________.
the density-dependent limiting factors for that population.
their carrying capacity.
population distribution pattern.
the size of the habitat that the population lives in.
3 of 20
What has helped human populations to increase their carrying capacity in their environments?
agriculture
the ability to build shelters
improved food distribution systems
all of the above
4 of 20
Lichens are one of the first pioneer species on a newly formed volcanic island in the Pacific Ocean. This is an example of ________.
competitive exclusion.
a keystone species.
primary succession.
an endemic species.
5 of 20
May develop in response to predation?
Mimicry.
Cryptic coloration.
Warning coloration.
All of the above.
6 of 20
A(n) _______tends to have a greater impact on community structure than their abundance in the community might suggest.
invasive species
keystone species
endemic species
exotic species
7 of 20
Opportunistic species typically_________.
are large bodied.
follow a type II survivorship curve.
experience little intraspecific competition for resources.
reach sexual maturity slowly.
8 of 20
The best example of secondary succession?
A retreating glacier leaves behind bare rock, which is then colonized by lichens.
A lake steadily becomes shallower and more nutrient-rich over time.
A 100-year flood recently occurred.
After plowing a field, the farmer decided to rest the field for the next season. Over the next few weeks, native grasses and wild flowers began growing in the field. Within a couple of months, small shrubs became established.
9 of 20
Competition among individuals of different species is _______ competition.
extraspecific
intraspecific
interspecific
exospecific
10 of 20
On average, the ecological footprint of an American will be ________the ecological footprint of someone from a developing nation.
larger than
smaller than
about the same as
not comparable to
11 of 20
Is the intentional release of a natural enemy to attack a pest population?
Biological control
Coevolution
Sustainable resource management
Integrated pest management
12 of 20
A species whose members produce only a few offspring and exhibits a high level of parental care _______.
is opportunistic.
will follow a type I survivorship curve.
will be uniformly distributed.
will follow a type III survivorship curve.
13 of 20
In the presence of limiting factors, what shape does a population's growth curve most closely resemble?
S
J
U
∩
14 of 20
Mutualism has ________on one organism, and ________on the other organism.
a positive impact; no impact
a positive impact; negative impact
a negative impact; negative impact
a positive impact; positive impact
15 of 20
Most likely to have density-dependent effects on population growth?
temperature
breeding site availability
fires
floods
16 of 20
Developing nations tend to have higher ______than more highly developed nations.
ecological footprints
life expectancies
ecological services
fertility rates
17 of 20
Level of ecology studies interactions between populations of different species?
Community
Organismal
Population
Ecosystem
18 of 20
A broad-based, pyramid-shaped age structure diagram for a human nation indicates that nation should consider ________.
planning additional retirement services for an aging population.
investing more significantly in childcare and youth education.
importing additional young workers to continue to generate adequate tax revenues.
encouraging people to have more children.
19 of 20
Random plot sampling is used to estimate ______, and the estimate will be the most accurate when the population is _______distributed.
population size; randomly
population density; randomly
population size; uniformly
population density; uniformly
20 of 20
Might be studied by an ecosystem ecologist?
competitive exclusion between two species of fruit flies
how the intensity of light impacts the distribution of algae in a stream
the use of mark-recapture to estimate the number of elk in the Kaibab National Forest of Arizona.
predator-prey interactions between the lynx and snow shoes hares
Answer:
It looks like Italy could be the closest
Explanation:
omg is that GOOOOOOOOOOOON lol sorry-
Especially considering it would have to be based off the how many children are alive because theyll be the future. And Italy is thinner than the U.S and Kenya.
Or I could be reading this incorrectly-
Complete the following sentence.
A farmer’s profit is determined by the amount by which the sale value of the ___ ___ exceeds the cost of production and distribution.
Answer:
profits farmers
Explanation:
Answer:
Crop yield
Explanation:
which structure could limits water loss in plants?
A) big leaves
B) waxy cuticle
C) phloem
D) non of above
Answer:
Big leaves cause water loss
Answer:
B) waxy cuticle
Explanation:
B) waxy cuticle
If a plant is an organism then the plants leaves, roots and stems are what level of organization?
What do you think medical professionals should do to prepare for when antibiotics don’t work any more?
Answer:
medical professionals should prepare for a backup plan i.e they should Always have other antibiotics in store
The primary purpose of Grameen Bank is to __________. A. provide loans to aid in building infrastructure in the world’s poorest countries B. provide installment loans to countries in economic crisis C. provide debt relief for poverty-stricken countries D. provide microcredit loans, especially to women Please select the best answer from the choices provided. A B C D
Answer: provide money
Explanation: it is most defintirle ej f
Answer:D. provide microcredit loans, especially to women
Explanation:
How is carbon moving between the air and found it decreasing
Answer:
Animals and plants need to get rid of carbon dioxide gas through a process called respiration. Carbon moves from fossil fuels to the atmosphere when fuels are burned.
The oceans, and other bodies of water, absorb some carbon from the atmosphere. The carbon is dissolved into the water.
Why are dead or weakened viruses used instead of normal viruses to create a vaccine?
because dead viruses aren't as effective as dead than "alive"
Make a claim about the types of wastes that the excretory system removes.
Answer:
Explanation:
Urea is the cellular waste product that the kidneys remove from the blood.Kidneys are the two bean shaped organs that has several functions to keep the body healthy. It not only removes urea from the blood, but also helps in the formation of urine and maintaining the fluid level of the body. The two kidneys are placed on the two sides of the spinal cord. The blood enters the kidney through the renal artery. The nephron within the kidneys mainly take out the waste products and the excess water from the blood and purifies it.If the kidneys of a person fail to work properly then it becomes important to perform dialysis for taking out the waste materials from the blood.
Which of the following is true of adaptive traits? they give organisms an advantage when it comes to survival
organisms with adaptive traits survive longer
organisms with adaptive traits produce more offspring
all of the above
on average how many toes does a human have? I think I have too many (not in a test, just wondering)
Answer:
10
Explanation:
we have 10 fingers and 10 toes
Answer:
10
Explanation:
We typicaly have 5 on the right foot and 5 on the left foot so 10 in total.
Hope that helps :)
what are 3 things needed for the formation of coal besides decayed living things?
Answer: Coal is mostly carbon with variable amounts of other elements; chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years.
Explanation:
Coal is produced from wood through decayed animals that burry down the earth and also start to deteriorate and behind millions of years they become coal.
How Coal is Formed?When Coal is primarily carbon with varying portions of different elements; oxygen, sulfur, chiefly hydrogen, and also nitrogen. Coal is produced from wood through decayed animals that burry down the earth and also start to deteriorate and behind millions of years they become coal.Coal is assembled when destroyed plant consequence decays into peat and is transformed into coal by the heat and intimidation of profound burial over millions of years.
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A car advertised states that it can accelerate from rest to 70 m/s in 7 seconds. What is its acceleration?
Answer:
10[tex]m/s^{2}[/tex]
Explanation:
Formula to find acceleration is :
Acceleration = [tex]\frac{ChangeInVelocity}{TIme}[/tex]
OR
Acceleration = [tex]\frac{Final velocity-Initial velocity}{Time}[/tex]
= [tex]\frac{70 - 0}{7}[/tex]
= [tex]\frac{70}{7}[/tex]
= 10[tex]m/s^{2}[/tex]
HELP I NEED HELP ASAP HELP I NEED HELP ASAP HELP I NEED HELP ASAP HELP I NEED HELP ASAP
HELP I NEED HELP ASAP HELP I NEED HELP ASAP HELP I NEED HELP ASAP HELP I NEED HELP ASAP
Petroleum and Natural Gas form from which of the following?
A. Radioactive materials
B. Fossilized remains of plants
C. Fossilized remains of marine organisms
D. Elements found deep within the earth
Answer:
Fossilized remains of marine organisms
A group of students used this diagram to classify three organisms into different kingdoms.
Multicellular
Cell wall
N No cell wall
Chloroplasts
No chloroplasts
No chloroplasts
2
3
Which table correctly identifies the three kingdoms?
A
Kingdom 1
Kingdom 2
Kingdom 3
Plantae
Fungi
Protista
с
Kingdom 1
Kingdom 2
Kingdom 3
Plantae
Fungi
Animalia
B
Kingdom 1
Kingdom 2
Kingdom 3
Fungi
Protista
Plantae
D
Kingdom 1
Kingdom 2
Kingdom 3
Animalia
Protista
Plantae
Answer:
option C
Explanation:
it fits the option well
Which statements are true? Check all that apply.
Answer:
A C and E i think
Explanation:
PLS HELP! THANK U :,)
Answer:
Yep C, seems like the most reasonable answer to the question.
2.
What happens in the process of photosynthesis?
A. Plants transform energy from the sun into chemical energy.
B. Plants use oxygen to store energy in food.
C. Animals use chemical energy in food to carry out life functions.
D. Animals transform energy stored in sugar into energy stored in fat.
Answer:
A, Plants transform energy from the sun into chemical energy.
This Is for today help!!
When facing potential threats, how does the endocrine system assist the immune system? A. The endocrine system releases hormones to prepare the body for response.
B.The endocrine system increases breathing rate and blood flow.
C.The endocrine system gives a physiological reaction in response.
D.The endocrine system allows for movement in coordination with the muscles.
Answer:
B
Explanation:
The endocrine system regulates oxygenation and blood perfusion.