Nitrogen makes up around 78% of the total atmosphere.
For which of the following activities might you want to hire a chemist?
Answer: D. testing a rock sample for gold content
Which of the following procedures involves a physical change in one of the substances?
Answer: C. separating a salt solution by evaporating the water
Answer:
v = 1.5 m/s
Explanation:
Given that,
Distance covered by a person, d = 105 m
Time taken, t = 70 s
We need to find the average speed of the person. We know that the average speed is given by :

So, the average speed of the person is equal to 1.5 m/s.
Answer: northern hemisphere
Explanation: I looked it up. Plus I took a test with this question and when the teacher went over the answer i got it right.