I think you're talking about histones. Histones are proteins found in eukayotic cell nuclei. Histones are what DNA wrap around so it fits inside the nucleus and helps with the formation of chromosomes.
Answer:
a
Explanation:
Remember, a biotic factors are those that are living (having life in them), while the abiotic factors are not living organisms.
Oxygen is in the category of biotic and it interacts with the atmosphere (space) which is abiotic.
Answer:
coevolution
Explanation:
Coevolution refers to the process where two or more species modify each other's evolution via natural selection. Darwin mentioned how insects and flowering plants could coevolve by reciprocal evolutionary modifications. Coevolution has firstly been associated with mutualism between species including, for example, birds and flowering plants. However, coevolution may also involve host-parasite relationships, such as associations involving parasitic organisms and their sexually reproducing hosts. Finally, there are situations where coevolution involves both parasitism and mutualism (i.e., antagonistic coevolution).
In the light dependent reactions light energy is absorbed by the photosytem II and an electron is released. This electron causes a process called photolysis to occur(H20-->2H++2e-+1/2O2). This is how O2 is released in the atmosphere. The electrons resulted from photolyisis enter the electron transport chain. In the electron transport chain using the energy in the elecrtons, hydrogen protons are pumped inside the thylakoid. Those protons accumulate to form an electrochemical gradient. That means the protons need to flow out, and they do through an enzyme called ATP-synthase which turns ADP and inorganic phosphate into ATP and water. In the electron transport chain, the electrons reach Photosystem I where NADP+ is reduced and becomes NADPH.
ATP and NADPH store the energy absorbed in the light dependent reactions. Those two molecules are needed when CO2 is fixated in Calvin's cycle to synthesize glucose.
