Guard cells become turgid when water flows in concurrently with
guard cells become turgid when water flows in concurrently witha. potassium ions. b.calcium ions. c.chloride ions. d.protons. e.sodium ions.

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.

When does the circulatory system work with the respiratory system? a. during blood cell formation b. during cellular respiration c. during intestinal digestion d. during a viral infection

Describe how a student should adjust the microscope to see the cells on a slide more clearly?