The answer is B.The respiratory system supplies the oxygen that the cardiovascular system transports to the different cells for the production of energy.
The uterine lining of the female's uterine cycle is shed during the menstrual phase. Menstrual cycle is a reoccurring cycle which begins at menarche and ends at menopause. During menstrual cycle, the endometrial lining prepares for pregnancy.
Answer:
The correct answer is B. the two strands of DNA must separate.
Explanation:
DNA is a double-stranded structure. The two strands are joined together by the formation of hydrogen bonds between complementary nucleotides. So before the replication takes place these two strands must be separated.
The separation of DNA strand is accomplished by the action of a helicase enzyme which breaks the hydrogen bond between complementary nucleotides and separated the two DNA strands.
After separation, the DNA polymerase binds to separated DNA and replicating the DNA. So the right answer is B.
