Plants exchange gases with their surroundings through openings in their Leaves, Stomata.
Xylem and phloem are the two tissues that are found within a vein.
Xylem carries water, and phloem carries food, or glucose.
Popliteus muscle
from: https://en.m.wikipedia.org/wiki/Popliteus_muscle
They are all chromosomal mutations but if i had to choose it would be A