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.

Match the following terms and definitions. 1. species that are adapted to live in equilibrium at carrying capacity population density 2. population growth that reaches equilibrium and carrying capacity population 3. death rate mortality 4. birth rate k-selected 5. a group of interacting individuals of the same species within the same geographic area natality 6. the number of organisms living in a particular area logistic growth