Which part of a cell allows certain materials to enter the cell and other materials to exit the cell

Blood has traveled from the heart to the toes. which describes the next step of the circulation process?

Residential construction is expanding in florida, the expansion has caused fragmentation of habitats, one of the results of the increased construction is a decrease in the number of large predators such as the coyote, black bear and pool panther, which will be the most immediate local result of this fragmentation? 1)large predators will become extinct 2)decrease in middle sized predators 3)increase in population of top carnivores 4)increase in population of prey species

What substance is the most acidic. lemon juice. tomato juice. sodium hydroxide. water