Cacti are plants that live in extremely dry environments. Unlike most other plants, cacti do not have regular leaves, but instead, have spines. They do have green stems. How would the lack of regular leaves help cacti survive in their environment?

answer; i believe that the correct answer is (lung);

b. lithosphere, asthenosphere, mesosphere   is the answer most likely

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.