Answer:
The role of cholesterol in the cell membrane is to maintain stability, anchor other molecules, and keep the membrane fluid in cold temperatures.
Explanation:
Sorry if it isn't right.
The black widow spider is an invertebrate. Its skeleton system hangs outside its body. The only difference between a vertebrate and invertebrate is the presence of backbone or a similar kind of structure with in the body. In case of black widow spider, the internal structural element is missing. Its skeleton system can be classified as exoskeleton.
Answer: Option A
Explanation:
Cyclin binds with an enzyme to produce MPF Cyclin, and as its concentration rises, it promotes mitosis.
Therefore, cyclin binds with a factor to produce MPF enzyme, and as the enzyme's concentration decreases, it promotes mitosis; the MPF Cyclin concentration remains constant, as the rise and fall of the MPF enzyme controls the cell cycle; the MPF Cyclin concentration increases and decreases in a cycle, but does not control the cell cycle are not best described the relationship between MPF and cell cycle.