Answer:
Hope this is helpful! Sorry if my answer is choppy.
Explanation:
Biotic and abiotic features are both important in ecosystems because for example, a biotic factor like a plant, relies on an abiotic factors like the rain and the sun. If the rain were non existent, then the plants would no longer be alive causing a chain reaction in the food system. Biotic factors like plants and animals that are non existent can also cause negative effects in biomes and ecosystems.
Answer:
The answer is the first option.
Explanation:
Farming emerged because being a nomad was no longer suitable for increasing population size. Farming allowed people to stay in one place and properly feed their families, which was a definite positive impact on population size.
Recombinant DNA is the answer
The question is incomplete. The complete question is:
Question: Why do organisms without oxygen need to convert pyruvate to lactate?
A) because pyruvate is toxic to the cells
B) in order to regenerate NAD+
C) in order to use lactate in the citric acid cycle
D) because lactate is needed to produce ATP
Answer:
B) in order to regenerate NAD+
Explanation:
Kreb's cycle and electron transport chain (ETC) are the aerobic stages of cellular respiration. ETC regenerates NAD+ and FAD+ by oxidation of NADH and FADH2 produced during glycolysis and Kreb's cycle. Here, oxygen serves as the terminal electron acceptor.
Glycolytic reactions use NAD+ as an electron acceptor and produce NADH. Therefore, a constant supply of NAD+ is required to sustain glycolysis. In absence of oxygen, ETC cannot occur and organisms convert pyruvate into lactate. Pyruvate is reduced in lactate and NADH serves as the electron donor. Thereby, lactate fermentation regenerates NAD+ to continue the process of glycolysis.
During middle age <span>an individual may experience initial decline of physical and mental attributes. This also increases during the last stage of life, old age.</span>
