Problem:OPTIONS:
- skin cells
- coded genes
- sperm and egg fuse
- hair cells
- the parent's sex cells
- lung cells
- male gametes
- reproduction

You are presented with the quiz "What can cause new alleles to appear?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "amutation in the sex cells of a parent can cause a new trait to appear in the parent 's offspring" and "alleles arise by mutation". So, what's the best answer to the question?
****
A: the parent's sex cells

Problem:OPTIONS:
- Final Symphonic movement
- illness
- positive
- fever
- allergic
- autologous transplant
- allogenic stem cell transplant
- sweating

You are presented with the quiz "Lymphocytes are a key cell involved in what type of reaction?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "lymphocytes are the key cells involved in the immune response" and "allergies are an immune system response". So, what's the best answer to the question?
****
A: allergic

Problem:OPTIONS:
- ferns
- sugar
- bushes
- naked mole rats
- rocks
- ice cubes
- alpacas
- shrub beds

You are presented with the quiz "What keeps itself warm naturally in the winter?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "some animals' fur grows thicker for staying warm in the winter" and "alpaca fur is one of the softest furs in the world". So, what's the best answer to the question?
****
A: alpacas

Problem:OPTIONS:
- reproduce
- Male infertility
- harm them
- bending light rays
- It expands
- allow growth
- Plant growth is reduced
- Damages them

You are presented with the quiz "What does changes in the structure of the Y chromosome do?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "mutations may change the structure of a chromosome or just change a single nucleotide" and "mutations in genes on the Y chromosome have been implicated in male genetic infertility". So, what's the best answer to the question?
****
A:
Male infertility