Which statement best describes the plasma membrane? a.) its rigidity does not allow materials to enter the cell. b.) it is freely permeable to all substances. c.) it is selectively permeable to certain substances. d.) it is nonpermeable to substances outside of the cell.

The image below shows a common blood pressure gauge. what does this device do? a. measures the level of oxygen present in the blood b. measures the pressure of blood when the lungs expand and compress c. measures the electrical activity of the heart d. measures the pressure of blood when the heart contracts and relaxes

Select all the offspring phenotypes that could be produced from a bbee x bbee cross (shown above). black fur, red eyes black fur, black eyes white fur, black eyes white fur, red eyes re la heller t est hulle elle l aila el answer : b & c b: black fur ,black eyes c: white fur , black eyes

How has biodiversity on earth changed over time?