Answer:
Rat. The laboratory rat, Rattus norvegicus, belongs to the order Rodentia and family Muridae. Rats were first used for experimental purposes in the mid 1800s. Strains were developed to study neuroanatomy, nutrition, endocrinology, genetics and behavior.
Explanation:
hope this helps you
While alive, an organism absorbs (radioactive) carbon 14 at such a rate that the proportion of carbon 14 in the organism remains at a known constant level. When it dies, it no longer absorbs carbon 14, so its proportion of carbon 14 begins to decrease. The half-life of carbon 14 is 5,600 years. A human skeleton is discovered whose level of carbon 14 is 15% that of a living human. To the nearest 100 years, how long ago did the person die
Answer:
The person has been dead for approximately 15,300 years
Explanation:
Available data:
The half-life of carbon 14 is 5,600 yearsThe human skeleton level of carbon 14 is 15% that of a living humanTo answer this question we can make use of the following equation
Ln (C14T₁/C14 T₀) = - λ T₁
Where,
C14 T₀ ⇒ Amount of carbon in a living body at time 0 = 100%C14T₁ ⇒ Amount of carbon in the dead body at time 1 = 15% λ ⇒ radioactive decay constant = (Ln2)/T₀,₅T₀,₅ ⇒ The half-life of carbon 14 = 5600 yearsT₀ = 0T₁ = ???Let us first calculate the radioactive decay constant.
λ = (Ln2)/T₀,₅
λ = 0.693/5600
λ = 0.000123
Now, let us calculate the first term in the equation
Ln (C14T₁/C14 T₀) = Ln (15%/100%) = Ln 0.15 = - 1.89
Finally, let us replace the terms, clear the equation, and calculate the value of T₁.
Ln (C14T₁/C14 T₀) = - λ T₁
- 1.89 = - 0.000123 x T₁
T₁ = - 1.89 / - 0.000123
T₁ = 15,365 years
The person has been dead for approximately 15,300 years
A researcher wanted to create a loss of function mutation for studying Type I Diabetes in a model animal. What mutation would mimic Type I diabetes?
a) Inhibition of sugar absorption in the small intestine
b) Inhibition of pancreatic beta-cells
c) Up regulation of insulin receptors on the pancreas
d) Down regulation of GLUT4 transporters in muscles
Answer:
The correct answer is: b) Inhibition of pancreatic beta-cells.
Explanation:
Type 1 Diabetes is a form of Diabetes Mellitus, a condition characterized by chronic hyperglycemia (high blood sugar levels) that can compromise many organs and even cause death if not treated properly.
The most common form of Diabetes Mellitus is Type 2 Diabetes, in which the pancreas produces insulin but cannot reach the target organs because of a pathologic state called Insulin Resistance.
Type 1 Diabetes, instead, is present in patients that cannot produce insulin on their own. Insulin is the most important hormone in the regulation of blood sugar - it is secreted by the pancreatic beta-cells when glycemia rises (which is normal after eating) and it is key in allowing glucose to reach the tissues where it's needed for energy requirements. Type 1 Diabetes is usually diagnosed in young, even pediatric, patients - the pancreatic beta-cells in these individuals are destroyed and unable to function (the reason for this is not clear in all cases), so they have to be administered with exogenous insulin to survive.
For the model animal to better represent Type 1 Diabetes, the mutation would have to inhibit pancreatic beta-cells.
A gene is
1. segment of DNA
2. All of our DNA
Answer:
segment of DNA
Explanation:
they contain the code for a specific protein that functions in one or more type of cells in a body
Answer:
segment of DNA
Explanation:
There are different parts of DNA.
One of them is the gene.
Have a great day.
The arctic fox has a diploid number of 50 an arctic fox was forming gametes by meiosis, how many chromosomes would be visible in prophase 17 Are the chromosomes replicated or non-replicated?
a. 2. 50; unreplicated
b. 28; replicated
c. 100, replicated
d. 25: unreplicated
e. 6.50; Replicated
Answer:
50 visible chromosomes and replicated.
Explanation:
Diploid number 50Haploid number 25When we talk about the cell cycle, we refer to the interphase and the cell division (mitosis or meiosis).
Interphase is composed of stages G1, S, and G2. During the S stage, the DNI replication process occurs. This is the only stage in which the DNI molecule replicates. The synthesis of histones and other associated proteins also occurs.
Meiosis occurs after the interphase is over.
Meiosis produces four daughter haploid cells (n) from a diploid germ cell (2n). Each daughter cell is haploid because they have half the number of chromosomes of the original one.
At the beginning of prophase 1, DNI is condensed in a well-defined chromosome formed by two sister chromatids joined by a centromere. Each chromosome carefully pairs with its homologous chromosome. Homologous chromosomes aline together to make the crossing-over possible, the stage where they interchange their parts.
The whole set of chromosomes is present in prophase 1. The reduction occurs later.
So if the germ cell has 50 chromosomes, the same 50 will be visible during prophase 1. DNA has already been replicated during the S stage of interphase.
Dehydration synthesis leads to WICH formation
Answer:
Polymers...........
Explanation:
Match each of the following muscles with its correct description.
a. sternohyoid
b. hyoglossus
c. frontalis
d. mentalis
1. originates on the sternum and clavicle
2. classified as an infrahyoid muscle
3. consists of two bellies
4. elevates and protrudes lower lip
Is there a particular type of fiber that is found mostly in the mucous connective tissue???
Explanation:
connective tissue. The fixed and transient cells found in connective tissue. ... Collagen fibers - most are type I collagen (most abundant protein in the body) ... It provides tensile strength in multiple directions. slide.
Which type of process occurs in the absence of oxygen?
cellular respiration
photosynthesis
fermintation
all of the above
photosynthesis prosecss in the absence of oxygen
on
Directions: Choose the correct answer listed from the box below and then
write the letter of your answers a separate sheet of paper for your
answers.
1. It is formed from the fossilized remains of prehistoric plants and
animals
2. An earth's material results from the rock fragments that have been
created physical weathering.
3. Another earth's material naturally occurred in solid substances that
are composed of ions and molecules bonded together.
4. The materials are derived from nature and used by the people to
survive or satisfy needs.
5. The place where natural resources are rich has fertile arable lands
and home to the largest metallic minerals
6. To use without being completely used up or destroyed
7. A practice to use the resources wisely
8. A renewable resource produces the most electricity
9. An energy resource that will run out in the next several years
10. Renewable energy coming from the sun
4.Non-renewable
E. Philippines
II. Sustainable
B Hydroelectric
F. Minerals
J. Fossil fuel
C. Soil
G. Natural resources
K. Solar Energy
D. Conservation
describe the internal diameter of the aorta.
Answer:
In sonographic measurements performed in the transverse view, the diameter of aorta (Ao) constituted 15.7 mm, the longer dimension of the inferior vena cava (IVC1) equaled 28.4 mm and the shorter one (IVC2) – 15.5 mm. In the longitudinal view, Ao equaled 15.3 mm and IVC – 18.8 mm (tab.
The strand of RNA moves to the ribosome.
The DNA double helix unzips.
The strand of RNA leaves the nucleus.
A protein is produced.
A strand of RNA is made from a strand of DNA.
The strand of RNA moves to the ribosome.
✔ 4
The DNA double helix unzips.
✔ 1
The strand of RNA leaves the nucleus.
✔ 3
A protein is produced.
✔ 5
A strand of RNA is made from a strand of DNA.
✔ 2
Which of these occurs in the first trimester of human pregnancy?
A. The fetus accumulates fat under its skin.
B. The fetus's lungs become fully developed.
C. The fetus is able to move its limbs.
D. The fetus becomes medically viable.
Answer:
i think its probably A
Explanation:
the first trimester is when the fetus enters a stage of rapid development. forming most organs, facial features, skeletal tissue, and limbs. So its either A or B. But i dont think the lungs are fully developed yet so i would choose A. hope this helped
B 3.1 Suggest which leaf carries out more photosynthesis and explain why. Below is a section of part of a plant as seen with a light microscope. (4) E e 3.2 Provide labels for: (a) different types of cells A, B and C (3) (b) structure D (c) The waxy, water-repellent layer E Provide a suitable heading for the above diagram (1) (1) 3.3 (1)
The leaf that carries out more photosynthesis is the bigger leaf since it has a larger surface area and will have more chloroplasts.
The labeled parts of the plants are found in the attachment.
A suitable heading is "parts of a plant".
What is the role of chloroplasts in photosynthesis?Chloroplasts play a crucial role in the process of photosynthesis, which is the primary means by which plants, algae, and some bacteria convert light energy into chemical energy.
Chloroplasts are the organelles where photosynthesis occurs, and they provide the necessary structures and molecules for capturing light energy, generating ATP and NADPH, and converting carbon dioxide into organic compounds.
They are essential for the survival and growth of autotrophic organisms and form the basis of the food chain on Earth.
Learn more about photosynthesis at: https://brainly.com/question/19160081
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water enters a long vurvykar tube at a eman tempreture taht is lower than the tine surface temperatire. The curve that most closely describes the mean tempretire of the fluid as a function of
Answer:
The curve that most closely describes the mean tempretire of the fluid as a function of position along the tube.
Explanation:
Hello. Your question is presenting very confusing words, however, through the context of the question as a whole, it is possible to see that you are saying that the water that enters a circular tube has a lower temperature than the temperature presented by the surface of the tube . In this case, if you are going to present a graph about this, it is important that this graph presents a curve that shows the relationship between the average water temperature as a function of the position of the water along the tube. This graph will be similar to the graph shown in the attached figure below.
What two different components of a telescope can be used to focus light?
Answer:
Mirror and Lens
Explanation:
Refracting telescopes use lenses to focus the light, and reflecting telescopes use mirrors
what is the main purpose of the pupil
Answer:
to adjust how much light is let into the eye
Explanation:
Answer:
The pupil is where light enters the eye. How much light is controlled by the iris which surrounds the pupil and opens and closes it like a camera lens aperture.
Birds differ from their closest relatives, the reptiles, in what ways?
(choose all that apply)
the bones of reptiles are too lightweight to permit flight
birds are capable of powered flight, while some reptiles can glide
birds have feathers, reptiles have scales
only the birds lay eggs on land; the reptiles can only lay their eggs in water
the reptiles have a series of internal air sacs that allow a very efficient extraction of oxygen
birds are endothermic, while reptiles are generally ectothermic
1 pts
Answer:
birds have feathers, reptiles have scales
birds are endothermic, while reptiles are generally ectothermic
Explanation:
The main difference between birds and reptiles is that birds have feathers on their body while on the other hand, reptiles ahve dry skin and have scales. Reptiles are ectotherms, while birds are endotherms. An ectotherm relies on its external environment to regulate the temperature of its body whereas Endotherms are able to regulate their body temperatures by producing heat within the body.
Why are temperatures hotter in locations near the equator?
Which gas is used by humans in the process of cellular respiration?
A) methane
B) nitrogen
C) oxygen
D) carbon dioxide
Answer:
oxygen is used by human in the process of cellular respiration
Who was newton please explain fast
Newton was a scientist in the 1600's who discovered gravity. He also discovered the laws of physics.
answer:
the man who discovered gravity by an apple falling on his head
hope this helps :)
Nonrenewable resources are those that cannot be replaced faster than they are used up by human populations. Do you think the resources you read about in this activity are nonrenewable? Explain why.
Answer:
first of all non renewable energy or resources is s energy or resources that can last for a particular time . such resources are depleted and cannot be replenished as the are used.
Explanation:
I think so because it is been recharged. e.g the phone been used is recharged or powered through electricity which can also be powered through waves of water from dams( kanji dams)
Why do some people argue that scientists should not use embryonic stem cells in medical research?
A. They think research conducted on these stem cells is not applicable to adults.
B. They think the use of these stem cells is too expensive.
C. They think the use of these stem cells is the same as ending a life.
D. They think research conducted on these stem cells is too difficult.
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D. They think research conducted on these stem cells is too difficult.
They argue because they think the use of these stem cells is the same as ending a life. Therefore, option C is correct.
This viewpoint is rooted in ethical and moral concerns. Embryonic stem cells are obtained from human embryos, usually from unused embryos created during in vitro fertilization (IVF) procedures. Opponents argue that using these stem cells for research purposes involves the destruction of potential human life since the embryos are destroyed in the process of harvesting the cells.
The ethical debate surrounding embryonic stem cell research centers on the question of when life begins and whether it is ethically justifiable to use human embryos for scientific purposes.
Learn more about stem cells, here:
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What type of frog or toad is this
Answer:
Explanation:
scaled reptiles
Answer:
this would be a black spot toad i think i am not 100 percent sure but its most probably this is a black spot toad
Explanation:
hope this help :]
How are cells able to guarantee that are DNA is always replicated correctly every time? 
Help will give brainl
Which of the following is a skin sensory receptor for touch?
A) Pacinian corpuscle
B) Meissner's corpuscle
C) Ruffini body
D) free nerve ending
Meissner's corpuscle is a skin sensory receptor for touch.
Meissner corpuscles are responsible for the sense of touch or light pressure, that is, they are very sensitive to the movement of objects on the skin and to very low vibrations.
About Meissner corpuscles:
• They are located on the lips and fingertips and are very sensitive.
• Meissner corpuscles act when there is a soft and light touch, and when vibrations are less than 50 hertz.
• These receptors can be altered when there is the presence of diseases where both thermal and tactile sensitivity are altered.
Therefore, we can conclude that Meissner corpuscles detect fine touch, that is, they are receptors on the skin that are sensitive to low-frequency vibration.
Learn more about Meissner corpuscles here: https://brainly.com/question/6963352
what happens to water when it boils
Answer:
When water starts boiling evaporation takes place
How does excretion takes place in amoeba
Answer:
excretion takes place through body surface by simple diffusion
Answer:
Amoeba is a unicellular organism living in fresh water bodies. The waste materials are excreted by the process of diffusion through general body surface. Contractile vacuoles also play some role in removal of waste materials.
hope it helps
have a nice day
Engineers design a system for heating the air in a house. They want the
heater to bring the temperature to a comfortable level and then maintain it.
Which option describes how the engineers should design the system?
O A. Include a control in the system that senses the air temperature
and causes negative feedback, reducing the output of the heater.
O B. Design the system with a control that maintains a constant level of
output from the heater.
C. Include a control in the system that varies the input level in a
regular cycle.
Design the system with a control that allows positive feedback to
enhance the heating ability of the system,
Answer:
I think its c include a control in the system that varies the input level in a regular cycle.
Explanation:
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The caterpillar, which is the larval stage of a butterfly, is very different from its adult form. Which phenomenon is responsible for this difference?
A. metamorphosis
B. regeneration
C. alternation of generation
D. molting
Metamorphosis IIRC, hope this help
Answer:
A
Explanation:
Metamorphosis is the process when large biological changes can occur like the transition from caterpillar to butterfly.
What are the three different ways a baby animal develops and what is it called?