The synthesis of nucleotides requires several amino acids. Identify each amino acid as a precursor in the synthesis of purines, pyrimidines, both purines and pyrimidines, or neither purines nor pyrimidines.

Hemoglobin is a proton that carries oxygen around the body what is hemoglobin made from

Which short-term environmental changes would a very small asteroid or comet impact on earth most likely cause? check all that apply. flooding extinction craters on surface changes in weather patterns death of organisms and populations

What class of levers is shown in this image?