Which best describes the structure of a phospholipid? a glycerol molecule between two fatty acid chains a lipid molecule with a polar head and a tail a phosphate molecule joined to a fatty acid a nonpolar molecule attached to a fatty acid

Select the correct answer from each drop-down menu. in an experiment, dr. travis examined the effects of calcium intake on osteoporosis, a condition that causes an increased risk of bone fractures. the amount of calcium is variable. the risk of bone fractures .

How can a geological time scale best be reconstructed? a) comparing vestigial structures in living species b) comparing homologous structures in living species c) examining homologous structures in fossil remains d) examining the written records of scientists from past cultures

What environmental cues and landmarks do the geese use to determine the timing and direction of their migration over the mountains? how do they find their way?