Abiologist studying a desert ecosystem of theirs at the population of a lizard species increases of following a particularly hot dry. that causes a snake population to decline what could the biologist hypothesis about the roles of these two species?
a) the lizard preys on the snake.
b) the lizard is a parasite of the snake.
c) the snake and lizard use the same limiting resource.
d) the snake is a keystone species in the ecosystem.

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.

Sweating and breathing is an example of differentiation specialization maintaining homeostasis metabolism

During an experiment, readings for blood pressure in a persons body were found to be constant . however , when he measured by a different blood pressure cuff , the readings differed by 15 points for each reading. this difference indicates that the results are