(a) describe the biological need for cells to be surrounded by a membrane that is selectively permeable for different materials

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.

i think its both a and b

answer: i feel like it would be 3

explanation:

answer;

c. a tree whose roots are surrounded by wet sand.

explanation;

water stress is an important factor limiting the growth and productivity of forests.water stress is the most often cited cause of poor survival and growth of woody landscape plants.

-insufficient soil moisture is the most common form of water stress, but excess moisture that leads to poor soil aeration (hypoxia) can also result in reduced plant vitality. a tree whose roots are surrounded by wet sand would be least likely to experience water stress.