Which step caused an aerobic atmosphere during the history of earth?
a. origin of cell membranes
b. an energetic atmosphere
c. origin of anaerobic prokaryotes
d. origin of photosynthetic prokaryotes

Define the apical impulse and describe its normal location, size, and duration. which abnormal conditions may affect the location of the apical impulse? explain the mechanism producing normal first and second heart sounds. describe the effect of respiration on the heart sounds. describe the characteristics of the first heart sound and its intensity at the apex of the heart and at the base. describe the characteristics of the second heart sound and its intensity at the apex of the heart and at the base.

Drag the tiles to the correct boxes to complete the pairs. match each cell organelle with its description.

What are the three groups of atoms that make up amino acids called