Correct answer: Option D- DNA ligase
Explanation: In option A, thymine is a nucleotide, so it is present throughout the replication process, wherever it is required. It is added to the newly formed DNA. In option B, Helicase enzyme is active during initiation and elongation stage, as it facilitates the opening of the winded DNA strands. Option C is nucleotidase and it has no role in DNA replication. So, the correct answer is DNA ligase, which is option D.
The okazaki fragments formed during DNA replication are sealed at the end. And in this step, DNA ligase is used. It catalyzes the formation of phosphodiester bond between the nucleotides of okazaki fragments. So it is the last active molecule of the process.
Placenta Previa
Placenta Previa is a disorder
that arises from the implantation and development of the placenta in the lower segment
of the uterine. The cause of this disorder is unknown. The three types of placenta
previa are complete, partial and marginal previa. The most common symptom of placenta
previa is painless bleeding during the third trimester.
Answer:
B.The sperm and egg.
<h3>....Hope it helps you.....</h3>
Answer: C. Dead snake fossilizing underground.
A fossil fuel is the fuel that is formed by natural processes, such as anaerobic decomposition of dead plants and animals underground. These organisms and their remains remain deep inside the depth of numerous layers of soil resulting in fuel produced after millions of years. A carbon sink refers to a natural or artificial reservoir that stores and absorbs atmospheric carbon by physical and biological process. The formation of fossil fuel inside the earth is carbon sink.
Dead snake will be added as a matter on which biological activity called as decomposition will take place. The organic matter of dead snake will be decomposed by microbes in the soil. The organic matter being the source of carbon, after decomposition will become the reservoir of carbon in the form of fossil fuel.
Therefore, dead snake fossilizing underground is the example of carbon source becoming a carbon sink.
You see, passive transport needs no energy. So that being said, it moves from areas with high concentration to areas with low concentration.
Hope that helps!
