What feature do plants have that provide structure and form?

a.

plants have an exoskeleton, like insects.

b.

plants have an internal skeleton of bones.
c.

plants have rigid tubes made of cellulose.

d.

plants have an external covering that keeps them upright

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

true is the answer : )