From studies and research, I believe the proper question would be:
"How do the animals satisfy their need for water?" or "How long do the animals live?"
Explanation 1:
When studying the desert, asking "Can you buy the animals in pet stores?" is not going to help you find information about the desert because it is not a question to get information about the desert, only information if you just buy it at your local pet shop.
Explanation 2:
Asking "How many offspring do the animals have?" does help us learn about animals, but we are trying to find information on the structure of the desert in which the animals live in. We are not looking for how many children the animals will have because it doesn't fully relate to the question we would be asking.
Side Note: Offsprings mean children.
<em>Hope this helps!</em>
<em> ~Hocus Pocus</em>
Answer:

point mutation, change within a gene in which one base pair in the DNA sequence is altered. Point mutations are frequently the result of mistakes made during DNA replication, although modification of DNA, such as through exposure to X-rays or to ultraviolet radiation, also can induce point mutations
Onion skin is a plant cell. And your skin cell is a animal cell.
Basically as simple all the structures in animal cell can be found in plant cells. But plant cells has some extra structure and part where doesn't exist in animal cells.
In animal cell, it contains a cytoplasm, nucleus and a cell membrane.
But in plant cell, they have chloroplast, cell wall and vacuole in additional.