What is the measurement of a population per unit area?

Which label correctly identifies what x represents in the concept map?

The cellular plasma membrane is selectively permeable, which means some materials move through it while others cannot. the movement of materials into and out of the cell is called membrane transport. this activity will you identify the different mechanisms of membrane transport

Which claim correctly describes how genes can produce a phenotype? one gene is responsible for all traits. each trait is determined by a single gene. one gene can be responsible for many traits. each gene is responsible for exactly one trait.