Question 2
Which single feature separates parenchyma, collenchyma and sclerenchyma from one another?
The right answer is the one marked above.
The nature of the cell wall. Thin and even in parenchyma, thickened at the corners in collenchyma, uniformly lignified in sclerenchyma. That one feature also decides whether the cell stays alive.
All three are simple permanent tissues, so cell shape and wall are what distinguish them — and of the two, the wall is the decisive one.