why can identical twins develop different diseases even though they have the same dna?
a their dna is replaced as they age
b they grow different numbers of chromosomes over time
c genes can be turned on or off in different ways
d one twin secretly mutates into a different genome
question 16
what did the mice in the lab demonstrate?
a color differences were caused only by mutations
b exercise alone explained all differences in weight
c different dna always leads to different appearances
d genetically identical animals can look and behave differently
question 17
why is the yellow mouse obese while the brown mouse stays thin?
a the yellow mouse has extra chromosomes
b the thin mouse is a twin mouse
c the agguti gene stays turned on in the yellow mouse
d the brown mouse has a different dna sequence

Question

Accepted Answer

### First Question (Why can identical twins...):
# Brief Explanations:
- Option a: DNA isn't replaced as people age, so this is incorrect.
- Option b: Chromosome number in humans is stable (46), so this is wrong.
- Option c: Epigenetics (gene expression regulation, turning genes on/off) explains phenotypic differences in identical twins with same DNA. This is correct.
- Option d: Identical twins have same genome initially, and "secret mutation" is not a valid explanation.
# Answer:
c. Genes can be turned 'on' or 'off' in different ways

### Question 16 (What did the mice...):
# Brief Explanations:
- Option a: Color differences in lab mice studies (like agouti mice) are due to epigenetics, not only mutations. Incorrect.
- Option b: Weight differences aren't explained by exercise alone; epigenetics/ environment play role. Incorrect.
- Option c: Identical DNA (same genotype) can have different appearances (phenotype), so this is wrong.
- Option d: Lab mice experiments (e.g., agouti mice) show genetically identical animals can have different looks/ behaviors due to epigenetic changes. Correct.
# Answer:
d. Genetically identical animals can look and behave differently

### Question 17 (Why is the yellow mouse...):
(Assuming typical agouti mouse experiment context, where yellow mice have the *Agouti* gene "on" leading to obesity, brown have it "off" or regulated. Let's analyze options, though some text is unclear, but from context:)
- Option a: Extra chromosomes not the case (mouse chromosome number is stable). Likely incorrect.
- Option b: "The thin mouse is a twin mouse" – not a valid scientific explanation. Incorrect.
- Option c: If "The AGOUTI gene stays 'turned on' in the yellow mouse" – this matches epigenetics (agouti gene expression leads to obesity in yellow mice, brown have it regulated). Plausible.
- Option d: Yellow and brown (in agouti experiment) are genetically identical (same DNA sequence, different expression). So this is wrong.
# Brief Explanations:
In agouti mouse studies, yellow mice have the *Agouti* gene overexpressed ("turned on"), leading to obesity, while brown mice have it regulated. Option c (assuming it's about Agouti gene being on in yellow) is correct. Other options are inconsistent with genetic/ epigenetic principles.
# Answer:
c. The AGOUTI gene stays "turned on" in the yellow mouse (assuming this is the option text, based on context)

Sovi.AI - AI Math Tutor

QUESTION IMAGE

Question

Explanation:

First Question (Why can identical twins...):

Answer:

Question 16 (What did the mice...):