The correct answer is option A
The major advantage of DDT at that time when it was used as a pesticide is that the DDT was very effective as a pesticide and it killed almost all the pests on which it was sprayed. It killed all the insect and pests that was present in the united states at that time. It later became harmful and entered into the food web.
Answer:
All of these choices are correct.
Explanation:
Cell cycle is the process of growth and division of cell. It comprises of interphase and mitosis. In interphase the cell grows, replicates its genomic content and prepares itself for division. In mitosis the division occurs.
Cell cycle is controlled by a group of kinases called as Cyclin dependent Kinases (CDKs). They act by phosphorylating their substrates. They are of various types like Cdk1, Cdk2, Cdk4 etc. They become active when they bind to a regulatory protein called cyclin. They are also of various types like Cyclin A, Cyclin B, Cyclin C etc. Level of cyclin and corresponding CDK increases and decreases according to the stage of cell cycle. For example in S phase of cell cycle concentration of cyclin A and E shoots up. CDK2 is able to bind to these cyclin molecules and hence it becomes active.
Cell cycle has major checkpoints where the condition of cell is analysed before it proceeds to the next stage of cycle. If any abnormality is detected, repair mechanism is activated or the cell is killed. Checkpoints do not allow cell cycle to proceed in damaged cells.
p53 is a tumor suppressor protein which can halt cell cycle when it detects some abnormality in cell. It usually acts in G1/S checkpoint (before the DNA replication starts in cell) and G2/M checkpoint (before the cell division begins). Hence, all of the above statements are true.
Golgi apparatus, not sure if my right but..
The correct answer that would best describe the given description above is the word SUPERCOILING. SUPERCOILING permits DNA <span>to maintain a relatively stable conformation when the helix is slightly underwound or overwound. It</span><span> </span><span>is</span><span /><span> an expression of the strain on that strand. Hope this answer helps. </span>
