In this experiment, you will determine which of four variables affect the breakdown of rock samples. to do that, you will change one variable at a time and then measure the change in mass of the rock sample. in the space below, write a scientific question you will answer by doing this experiment.

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.

Vaccines are weakened forms of disease causing microorganisms, which are given to patients to prevent disease. after the vaccine is administered, the immune system responds by creating a(n) to recognize the a.) antibody, antibiotic b.) antigen, antibody c.)antibiotic, antibody d.)antibody, antigen

Which is an example of a vestigial structure? a. tail of a monkey b. fin of a fish c. flower of a plant d. tailbone of a human