Answer:
<u>d. Transport proteins within the membrane serve as a tunnel for molecules to enter the cell.
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Explanation:
Solutes are typically moved across the cell through either passive or active transport. The cells, surrounded by a bilipid layer or plasma membrane is amphiphlic- its polar, hydrophilic lipid heads face outwards, while their non-polar hydrophobic lipid tails face inwards towards each other.
While lipid-soluble molecules move across the layer easily, it is also difficult for charged and also large molecules to move across its surface, into the cell. Transmembrane channels, <u>embedded within the membrane</u>, help to maintain selective permeability as transport proteins, pores and gated channels. Simple diffusion happens as a method of passive transport in cells through plasma membranes.
The solutes travel through the plasma membrane in the process of diffusion from regions of high concentration to regions of low concentration; this occurs without the use of energy. <u>Molecules moving against their concentration require active transport mechanism to cross the membrane</u>.
Answer: D) Centrioles
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Centrioles are only found in animal cells and they help during cell division. They organize the spindle fibers that help elongate the cell and separate the chromosomes.
<span>Radiochemical dating is the answer!</span>
The answer would be: <span>Make sure the landing page is closely related to the ad
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To have high conversion rate, the landing page should give an accurate advertising that closely related to it. Increasing the budget will increase the conversion number, but not the rate. Increasing the CPC bid or broaden the list of keyword won't increase the conversion rate either.
At first, the population of predators would spike and increase quickly, but then over time, gradually decrease.
(This is because at first there's more food, so the predators population increases. But overtime it begins to level out and the predators' population catches up with the prey, and in result, doesn't continue increasing.)
