Greenhouse gases absorb radiation from the sun and read it back to the atmosphere which helps to maintain a normal range of what on earth?

Describe your dna model. which part do the straws represent? the pushpins? the paper clips and the black dots you made with the marker?

Facilitated diffusion move large molecules and/or polar molecules across the cell membrane. what does facilitated diffusion use to do this?

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