Mitochondria and chloroplasts are thought to have been
a. free-living prokaryotes
c. protocells
b. early forms of eukaryotes
d. spontaneously generated

Drag each label to the correct location on the image. g organisms adopt different strategies and structures to make sure their offspring it uses. herds young into center of group produces many offspring at once to protect against high predation risk protects offspring until environmental conditions are ideal for growth coo b 13 1994 7 odos si . an . i

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

Amylase is an enzyme found in the human digestive system. why do you think it was important to keep the enzyme temperature above 37 degrees celsius (98.6 degrees f)? describe what might happen if the temperature decreased by 10 degrees celsius.