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.
Answer:
<h2>a rift valley is forming</h2>
Explanation:
Answer:urbanization is responsible for the loss of vegetation and soils.
Explanation:
As urbanization alters the natural amount of water that takes each route.
Answer:
The small population of zooplankton have an unequal effect on the marine community.
Explanation:
According to this question, there are three trophic levels of organism in a lake as follows: non-native fish, zooplankton, and algae. However, due to the declination in the number of zooplanktons in the lake as they were fed on by the non-native fish, the algal population increased to form a BLOOM.
This bloom of algal species can be attributed to the lack of zooplanktons, which represented the only herbivorous (plant eaters) organism in that community. Hence, their relatively small population have an unequal effect on the marine community. This means that the small population of zooplanktons caused an imbalance in the community and this is why ZOOPLANKTON is the keystone species in this scenario.
The answer is B, because salt water has lots salt, and little water. The cells lose their water content and fill up with salt, causing ti to collapse.
