Cholesterol is an important component of animal cell membranes. cholesterol molecules are often delivered to body cells by the blood. which transports the molecules in the form of cholesterol- protein complexes. the complexes must be moved into the body cells before the cholesterol molecules can be incorporated into the phospholipid bilayers of cell membranes. based on the information presented, which of the following is the most likely explanation for a buildup of cholesterol molecules in the blood of an animal? the animal's body cells are defective in exocytosis. the animal's body cells are defective in endocytosisy c) the animal's body cells are defective in cholesterol synthesis. (d) the animal's body cells are defective in phospholipid synthesis.

The most likely explanation for a buildup of cholesterol molecules in the blood of an animal is that 'the animal's body cells are DEFECTIVE in endocytosis'.

Endocytosis refers to the movement of molecules from the surrounding cellular environment to the interior of the cell by transport vesicles.

This process (endocytosis) is caused by the invagination of the cell membrane to form an intracellular vesicle that contains extracellular fluid.

Cells absorb cholesterol from their surrounding extracellular environment by receptor-mediated endocytosis.

In conclusion, the most likely explanation for a buildup of cholesterol molecules in the blood of an animal is that 'the animal's body cells are DEFECTIVE in endocytosis'.

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The correct answer is - option B. The animal's body cells are defective in endocytosis.

Explanation:

Endocytosis is the process that internalized the substances inside the cells by the area surrounded by the membrane. This is the process that helps in the internalize cholesterol-protein complexes.

If the cells are not able to perform this then cholesterol-protein would not be internalized by the cell and it will remain in the blood and buildup cholesterol molecule.

Thus, the correct answer is - option B.

thrombocytopenia, which is a deficiency in blood platelets, can cause bleeding and bruising in the dermis similar to senile purpura. other possible causes include: exposure to ultraviolet rays and aging skin are common causes of senile purpura. senile purpura may also be a sign of collagen loss in the skin and bones.

the oldest known insects are believed to live around 400 millions ago as suggested by the fossil records.   some plants having woody stems also evolved during this time.

after the evolution of insects the first four legged species or the tetrapods evolved in shallow freshwater habitats from the intermediate species approximately 397 million years ago. the tetrapods went on conquering the land giving rise to amphibians, reptiles, mammals and birds.

the major split in tetrapods first occurred 340 million years ago branching off from amphibians.

363 million years ago when the carboniferous period began the insects started roaming on land and taking flights, following which the four limbed tetrapods adapted in the terrestrial habitat.