D. A struggle for existence is apparent.
If a struggle for existence is apparent, natural selection occurs because all of the weak/unfit/unadapted ones die.
Sister chromatids are two identical copies of Chromosome that is formed by the replication of a single chromosome.
This copies are formed during mitosis. Later on, these two sisters chromatids will grown into two different Cells
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Answer:
b.Movement of phospholipids in the plasma membrane from one monolayer to the other requires the polar or charged head groupd to enter the hydrophobic interior of the lipid bilayer. This process requires a large positive change in free-energy, thus making this type of movement unlikely without an input of energy
The plasma membrane serves a protective function for the cell and is a selective membrane for particles entry
Glycolysis, the first process in cell respiration, produces four ATP, but it uses two of the ATP molecules, therefore producing a net two ATP molecules. The process also yields two molecules of NADH.Glycolysis begins with glucose and breaks it down into two molecules of phosphoglyceraldehyde.
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