<span>Extreme temperature and bedrocks
Tundra and desert both have shallow soil profiles because of the extreme temperatures and the bedrocks it has. In the case of tundra, it has extreme cold temperature and the soil were covered in ice in long periods of time. Because of this, the plants were unable to get water from the bedrocks resulting in plants dying. In the desert, however, it has extreme hot temperature making the plants unable to survuve due to lack of water in the environment and in the bedrocks. The plants that can only survive in this temperature are the plants that has the ability to store water in their system.</span>
The correct answer is the second option. Animals have two major types: vertebrates and invertebrates. Vertebrates are animals that have backbone while the invertebrates do not have one. Examples for vertebrates are birds and mammals while the latter are insects and squid.
B- speed up the chemical reaction
Other molecules such as proteins, starch and sugar are simply too large to diffuse across the membrane. Sometimes, some of these large molecules are transported across the cell membranes by carrier proteins; this does not require energy and as a result is a form of passive transpor