What does it mean for a membrane to be selectively permeable?

only certain molecules are allowed to pass through.

the membrane is rigid and only allows water to pass through.

all types of molecules are able to pass into the cell.

the membrane is rigid and nothing can enter or leave the cell.

Describe the response the kidneys have to dehydration and excessive water intake. what happens to the concentration of urine in each case ?

Which sentence best describes the relationship between chlorophyll and the chloroplast? a.) chlorophyll is a chemical found in a chloroplast. b.) chloroplast is a chemical found in a chlorophyll. c.) both chlorophyll and chloroplasts are found in animals. d.) both chlorophyll and chloroplasts make carbon dioxide.

Identify the composition of oceanic and continental crystal rocks.in a model of earth’s interior,where would these rocks appear?