Jet streams are fast moving air currents much like how a river is a fast moving water current so the answer is jet streams.
Comparing DNA
Darwin could compare only the anatomy and embryos of living things. Today, scientists can compare their DNA. Similar DNA sequences are the strongest evidence for evolution from a common ancestor. Look at the diagram in Figure 9.3
experiment to determine how the type of food source available affects the rate of cellular.
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:
∴
