The exchange of gases between the alveoli and capillaries of the lungs happens because of what?
the movement of substances from an area of high
concentration to an area of low concentration

the answer is "a.) well–developed vascular system."

explanation:

as in mitosis, dna replication occurs during interphase.   in meiosis, it occurs specifically in s phase of interphase 1.

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.