What do all living organisms have in common?A. They all reproduce asexually. B.They all perform photosynthesis. C.They all release oxygen into the Earth's atmosphere. D.They are all made of one or more cells.

D

Explanation:

Only some organisms reproduce asexually, only plants perform photosynthesis, and most creatures consume oxygen and release carbon dioxide. D is the correct answer both by process of elimination and because the simplest life form is the single celled organism, which still has one cell. All complex life is made out of many many many cells.

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:

answer: 21

step-by-step explanation:

divide 630 by 30. 30 goes into 630 21 times