To
1. choose the correct order of events in the kreb's cycle:

the correct order of krebs cycle is

Explanation:In the first step of the citric acid cycle, acetyl CoA}CoA, C, o, A, end text joins with a four-carbon molecule, oxaloacetate, releasing the {CoA}CoAC, o, A, end text group and forming a six-carbon molecule called citrate.

Step 2. In the second step, citrate is converted into its isomer, isocitrate. This is actually a two-step process, involving first the removal and then the addition of a water molecule, which is why the citric acid cycle is sometimes described as having nine steps—rather than the eight listed here

Step 3. In the third step, isocitrate is oxidized and releases a molecule of carbon dioxide, leaving behind a five-carbon molecule—α-ketoglutarate. During this step,

s, N, A, D, is reduced to form N, A, D, H, end text. The enzyme catalyzing this step, isocitrate dehydrogenase, is important in regulating the speed of the citric acid cycle.

Step 4. The fourth step is similar to the third. In this case, it’s α-ketoglutarate that’s oxidized, reducing {NADH} NADH and releasing a molecule of carbon dioxide in the process. The remaining four-carbon molecule picks up Coenzyme A, forming the unstable compound succinyl , C, o, A, end text. The enzyme catalyzing this step, α-ketoglutarate dehydrogenase, is also important in regulation of the citric acid cycle.

dit: modified from "Oxidation of pyruvate and citric acid cycle

Step 5. In step five, the C, o, A, is replaced by a phosphate group, which is then transferred to. In some cells, —guanosine diphosphate—is used instead of —guanosine triphosphate—as a product. The four-carbon molecule produced in this step is called succinate.

Step 6. In step six, succinate is oxidized, forming another four-carbon molecule called fumarate. In this reaction, two hydrogen atoms—with their transferredThe enzyme that carries out this step is embedded in the inner membrane of the mitochondrion, so it can transfer its electrons directly into the electron transport chain.

Step 7. In step seven, water is added to the four-carbon molecule fumarate, converting it into another four-carbon molecule called malate.

Step 8. In the last step of the citric acid cycle, oxaloacetate—the starting four-carbon compound—is regenerated by oxidation of malate. Another molecule of NADPH

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.

4.) metal

"-the movement of carbon from the nonliving environment into living things and back to the environment

-carbon is the essential component of proteins, fats, and carbohydrates (which make up all organisms)

-carbon exists in air, water, and living organisms

-producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis

-bacteria in the atmosphere cycles through the system in filtration units

-in cellular respiration, carbon is released back into the atmosphere as carbon dioxide

-some carbon is stored in limestone (forming one of the largest "carbon sinks" on earth)

-largest carbon reservoir on earth= limestone

-carbon stored in the bodies of organisms as fat, oils, or other molecules may be released into the soil or air when the organism dies

-this may form deposits of coal, oil, or natural gas (fossil fuels, which increased the atmospheric carbon dioxide)

-fossil fuels store carbon left over from bodies of organisms that died millions of years ago

-they are located in the surface of earth, deep within the earth and beneath the ocean floor."