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:
∴

Answer:
I'm pretty sure the answer is 4.
Explanation:
1 and 2 are definitely homeostasis because it is a way to keep your body balanced how it needs to be and 3 would be a natural reaction that your body would make to prevent further pain, but 4 would be a personal choice that is made by the person who stays up.
The answer would be B) Sponges, corals, worms, insects, spiders and crabs are all sub-groups of the invertebrate.
Single cell division is mitosis i think