Ablastocyst is a
a. cluster of cells surrounding a developing egg in the uterus
b. membrane that surrounds and protects a growing embryo in the uterus
c. growth that conform in the wall of the fallopian tubes
d. hollow ball of cells formed after a fertilized cell undergo cell division

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.

All eukaryotic cells contain small bodies called

If there are 350 trout found in 200 square feet of a pond measuring 1000 square feet what is the estimated trout population of the pond? a. 1350 b. 1550 c. 1750 d. 2000