HELP PLEASE An organic molecule that acts as the main energy source for cell processes. It is a carbohydrate and a product of photosynthesis.

a. oxygen

b. hydrogen ion

c. chlorophyll

d. glucose

20 the main source of energy for our planet comes from the

What two factors does carrying capacity compare? population size and resource use population growth and resource availability resource use and time population size and time

Crinoids, also known as sea lilies, appear to be sea plants but are not plants at all. crinoids are an echinoderm species which uses anchoring structures called holdfasts to attach themselves to the sea floor. crinoids were most abundant in pennsylvania during the mississippian period, which ranged from 375 to 320 million years ago. fossils of the crinoids shows that during most of this time pennsylvania was that provided favorable conditions for crinoid growth. a) glacial terrain b) a dry and sandy plain c) mostly mountain ranges d) covered by warm, shallow seas