Answer:
D. service
Explanation:
Most people in the US work in jobs that require providing a service to others, whether it's at a restaurant, a department store, a school, etc. Yet, those who work in specialised jobs like agriculture, fishing, and mining are more rare because they need to live in a certain area that is optimal for such positions.
Thus, the answer is D.
Answer:
C.facilitated diffusion
Explanation:
Because it have some chemicals did you breathe from the person who using cigarettes.
Answer:
Insulin causes the body's cells to take in and store glucose, lowering the blood glucose concentration. If blood glucose gets too low, the body releases glucagon, which causes the release of glucose from some of the body's cells.
Explanation:
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.
