Answer:

Explanation:
We recognize that total occurrence equals new cases of disease over time divided by the number of people at risk at the onset.
Mathematically:

Given that:
Number of the population at risk = 1000 individuals
New cases during Jan 1 - Dec 31 = 60 because;
At 20 occurred on June 30 & 40 on Sept. 30) & no new cases were identified after that:
∴

Megacity would probably have the biggest affect on the immediate environment and possible the outlands of the megacity as well.
Answer:
A, C
Explanation:
mucus acts as a barrier! all of the other things mentioned (D and E) are caused by white blood cells.
C is the answer to this question.
Answer:
When the inside of the Earth was liquid, gravity caused the heavier elements nickel and iron to sink to the center. Lighter elements floated to the surface. Over time this process caused the Earth to separate into layers.
Explanation: