Which is a carbohydrate?
amino acid
nucleotide
polysaccharide
nucleic acid

Each pair of clay balls represents two planetesimals. if each planetesimal is composed of the same material and is separated he the same distance, which pair experiences the frayed gravitational attraction?

Greenthe fossil record is the history of life recorded byhuman observationgod.climatologists.remains of the past.

This is a scaffolding of protein fibers that us sell keep it shape in a cell division and cell movement