True or False, it's likely that organisms other than LUCA existed alongside LUCA before the divergence of bacteria from archaea and eukaryotes.

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.

Which of these internal feedback reactions does not need your brain? oa. your leg jumping when it is hit by a reflex hammer b. your deeper breathing when you need more oxygen c. your body temperature rising when you have an infection d. your heart beating faster when you are in danger

When wind creates a sand dune, the sheltered side of the dune is less steeply sloped than the windward side has the same incline as the windward side is more steeply sloped than the windward side