<span>The organism will produce 12 chromosomes (A).
Sex cells are the products of meiosis. Daughter cells of meiosis contain half the number of chromosomes of the parent cell. So if the parent cell has 24 chromosomes, then the sex cell would have <em>12 chromosomes</em>.</span>
C. The nervous system sends signals to make muscles move.
The correct answer is: A checkpoint will be activated if the spindle does not attach to a kinetochore.
Prokaryotes, do not undergo mitosis (like eukaryotes) and therefore have no need for a mitotic spindle. Prokaryotes also don’ t have checkpoints foor the regulation of cell division.
Normal eukaryotic cells (unlike cancer cells), move through the cell cycle in a regulated way in order to make sure that cells don't divide under conditions that are unfavorable for them. Information about their own internal state (nutrients, signal molecules, DNA integrity) is signal to go or not to go through the cell division. Because of that there are few checkpoints in the cell cycle at which the cell examines the signals and makes a “decision”. The major checkpoints are:
• The G1- the first point at which it must choose, once it passes the G1 checkpoint the cell enters S phase
• The G2-the cell checks DNA integrity and checks if replication is done well.
• The spindle checkpoint-at the transition from metaphase to anaphase.
The general theory is that mitochondria and chloroplasts began initially as separate cells that were "eaten" by larger cells, but not digested and simply passed on due to their advantages.<span />
