I'll answer what i can
Answer:
Its recommended because it can help fight the flu if you get it
It affects the immune system by training it to target the flu, and gain resistance to it
The best time is during cold, due to the fact that cold helps the virus (heat kills some viruses)
depending on the person depends on whether its effective or not.
<h2><u>Recommended for taking it, i do not know. Sorry for the missing answer.</u></h2>
Its important for the CDC to update it every year because the flu isn't always the same, and can adapt to the shot to where it has no effect.
The gradual evolution for the family Equidae (horse family) has been well documented within the fossil record.
Since the death rate is higher than the birth rate we can assume that it will be negative. 5-15 is -10 for their life. immigration is also lower than the emigration. 2-4 is -2. adding -2 and -10 will give us -12, hope this helps.