The answer that makes the most sense is number one or two. Number 3 and number four both makes no sense in that context. Most of the time an animal will not die or mutate due to a parasite in its body.
They do not have a cell wall because only plant cells have that. The plant cells have that to help with the process for creating the green color. The animal cells, instead, they have a cell membrane.
I think it is the second answer, sorry if it is wrong/didn’t help.
Explanation:
A genetic trait that helps an organism be more successful in its environment
The nucleus? budding is when two cells reproduce asexually