Answer:
Im not 100 percent sure but I think C because a chemical change occurs when the chemical has broken composure so I think its C.
You're correct because when birds hit their max altitude it's harder to breathe and to minimize the time of there flight they store immense amounts of oxygen in their lungs.
Answer:
Hello!
A mineral that is a secondary nutrient for plants is <u>calcium.</u>
Hope this helps!
<span>Answer:The blood-brain
barrier (BHE)
BHE is a barrier that's highly permeability selective and protects
the central nervous system from potential dangers like viruses, bacteria and parasytes that may be circulating int he blood. <span>It is composed of endothelial cells, astrocytes, pericytes.</span></span>
