Respiration happens only with the presence of oxygen (Explain your answer) A) True
B) False

Give me the explanation
And also give me a real answer

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.

Despite the differences in mature plant cells, all of them are derived from meristem cells. the three major types of tissue systems develop from the meristem. meristems develop cells in all but which tissue?

What were the main components of earth’s earliest atmosphere? oxygen and ammonia hydrogen and helium oxygen and nitrogen hydrogen and nitrogen