<span>Cenozoic
</span><span>Mesozoic
</span><span>Paleozoic
</span><span>Precambrian </span>
Answer:
Cell membranes are composed primarily of fatty-acid-based lipids and proteins.
Explanation:
a long, seismically active submarine ridge system situated in the middle of an ocean basin and marking the site of the upwelling of magma associated with seafloor spreading. An example is the Mid-Atlantic Ridge.
<h2>THIS IS THE GOOGLE DEFINITION*</h2>
Answer:
A
Explanation:
a. contain checkpoints that determine if the cycle will continue.
b. help move chromosomes to the new daughter cells.
c. produce more chromosomes before the cell divides.
d. grow and produce enough cytoplasm to fill two cells.
<em />
<em>The correct answer would be that G1 and G2 contain checkpoints that determine if the cycle will continue or otherwise.</em>
The cell cycle generally has three checkpoints that happen at G1, G2, and M phase of the cycle.
At G1 checkpoint, the integrity of the DNA of the cell is assessed to ensure that there are no damages and other conditions such as size and energy reserve are checked.
At G2 checkpoint, the cell is assessed for proper chromosome duplication to ensure that there are no mistakes or damages. The size of the cell and the amount of protein are also checked to ensure that the cell is ready for the active division phase.
At M checkpoint, correct attachment of the spindle fiber to the kinetochore of the chromosomes is checked. This checkpoint is also known as the spindle checkpoint and it happens towards the concluding phase of the metaphase stage.
<u>The correct option is therefore, A.</u>
