The net annual primary productivity of a particular wetland ecosystem is found to be 6.000 kcal/ myr. If respiration by the aquatic producers is
19.000 kcal/
myt, what is the gross annual primary productivity for this ecosystem, in kcal/
myr?
4.000 kcalm
6.000 kcal/
myr
Oь
10.000 kcal/
mt
16,000 kcal/
myr

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:

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.

c is the correct answer!