C? i think..................
Radioactivity is the emission of a particle from am atom. Fission is splitting an atomic fusion is combining two nuclei into a new atom and a meltdown refers to a disaster at a unclear power plant. Your answer is D.
Answer:
C. active transport, because protein pumps are needed to move substances against a concentration difference
Explanation:
There are two major types of transport in living cells namely: passive transport and active transport. The passive transport moves molecules down a concentration gradient and hence, do not need energy (ATP) to occur. However, on the other hand, ACTIVE TRANSPORT moves substances against their concentration gradient, thus, require energy input.
Active transport makes use of PROTEIN PUMPS to achieve this process. Hence, in this case where Alexis is using models of the cell membrane to compare the types of cellular transport. The model that shows a molecule entering through a protein pump is modelling ACTIVE TRANSPORT.
Is any member of a large class of gaseous, liquid, or solid chemical compounds<span>whose molecules contain carbon</span>
Scientists combine several well-testedtechniques to find out the ages of fossils. The most important are Relative Dating, in which fossils and layers of rock are placed in order from older to younger, and Radiometric Dating, which allows the actual ages of certain types of rock to be calculated.