Chemically speaking, enzymes are composed of chains of , and they are considered to be a type of.

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:

it is called the mitotic spindle

answer; ///blank(1); green bananas; blank(2); raw potatoes;