Answer:
D. Active transport.
Explanation:
Active transport is the method that uses the ATP's energy to move ions and molecules from one side to the other of the membrane. The elements move from a place of lower concentration to one of a higher concentration. They move against their concentration gradient, which is why they need the energy to do it. There are two types of active transport, primary and secondary.
The primary active transport is ion pumps that hydrolyze ATP using one of the phosphates of the ATP to change the pump's shape and move the elements against their concentration gradient. It uses the ATP's energy directly.
The secondary active transport does not use ATP directly. It uses the electrochemical gradient that the primary transport had created when hydrolyzing ATP to transport the ions and molecules.
Well all cells in a multicellular organism have the same exact DNA (except for sex cells). But what makes each type of cell different physically and functionally is the genes that are expressed in those cells.So for like example a different section of the DNA molecule is expressed in a nerve cell than a skin cell.
Answer:
250 years
Explanation:
The Atlantic Ocean is not static, but instead it is very active, and it is actually spreading from its central part. In its central part, this ocean has a mid-ocean ridge. This basically means that there is constant formation of new crust from the magma that comes out, and the old crust is pushed sideways as the new one is formed. On an annual level, the mid-ocean ridge is spreading out by an estimated 0.02 meters, thus that is how much the Atlantic Ocean is spreading out each year. In order to get to the result as to how many years are needed for the Atlantic Ocean to spread 500 cm, we just need to multiply the annual spreading with the number of cm in question:
0.02 x 500 =250
Thus we get a result of 250, meaning that in 250 years the Atlantic Ocean will spread out 500 cm in total.
Option D – amphibians may use their skin for gas exchange is the characteristic feature of amphibians that differs from reptiles.
Explanation:
The amphibian skin is moist, thin and marbled and supplied by blood vessels running on its surface. The moisture present in the skin dissolves the oxygen present in its surrounding which is absorbed by the blood vessels. Special glands help the amphibians to keep the skin moist.
The very thick and tough scales present on the reptiles prevent them to absorb oxygen through their skin. Hence, they breathe and respire through their lungs.
Amphibians have three-chambered heart. They do not develop amniotic eggs. Adult amphibians although spend much time on land, they breed only in water due to the absence of amniotic sac
.
