Answer:
The correct answer is C) ensures the continued existence of the human species.
Explanation:
The human reproductive system is responsible for the production, storage, and transfer of gametes to the next generation. In the male reproductive system, testes make gametes and in the female reproductive system, ovary makes gametes.
The reproductive system in humans ensures the continued existence of human species in this world because the reproductive system is responsible for gamete fusion and new offspring developments which are more adapted in the environment. This ensures the existence of humans on earth.
In the Grand Canyon, there are clear horizontal layers of different rocks that provide information about where, when, and how they were deposited, long before the canyon was even carved.
Answer: After 3 rounds, 8 segments having 2 original strands on different segments will be present.
Explanation:
The polymerase chain reaction selectively and repeatedly copy the double stranded DNA (dsDNA) in the PCR machine.
1st round:
Single piece of double stranded DNA (dsDNA) unwinds in two seperate strands, before complementary nucleotides are synthesized to establish double helix.
2nd round:
The two dsDNA yields 4 segments before complementary nucleotides are synthesized
3rd round:
The four dsDNA yields 8 segments before complementary nucleotides are synthesized.
Therefore, at the end of 3 rounds, the two original strands will be present on the 8 different segments of copied DNA.
Answer:
b: 8;8
Explanation:
Mitotic or meiotic cell division constitute the m phase of the cell cycle. At the end of the m phase, the new cells enter the interphase stage of the cell cycle. The interphase is further sub-divided into;
- <em>the
phase,</em> - <em>the
phase,</em> - <em>the S phase; and</em>
- <em>the
phase</em>.
The phase is essentially a resting phase. Cells that do not need to divide except when necessary move into this phase after exiting the m phase.
Actively dividing cells enter the phase after exiting the m phase. Cell development and growth takes place. From there, the cells enter the S phase where DNA replication/synthesis takes place. The cells then enter the phase where proteins are synthesized in preparation for division or m phase.
At the S phase, the amount of DNA a cell carries is doubled but the chromosome number remains the same. For example, if a cell enters the S phase with 2 g of DNA containing 10 chromosomes, at the end of S phase, the amount of DNA would have come 4 g while the number of chromosomes will remain 10.
Hence, if the average amount of DNA in the assayed cells immediately after mitosis is 4 picograms, the amount would be 8 picograms at the end of S phase and will still remains 8 picograms at the end of phase.
The correct option is b.
