I checked all answers on Photomath.
Let me know if that’s helpful.
Answer:
Step-by-step explanation:
To find the values of the angle which makes maximum r you use the derivative of r

If you equals this derivative to zero you obtain the value of the angle:

However, the values of 5π/6 and 9π/6 are also available, because makes the sinusoidal function equal to 1.
hence, the answer is:

answer b
It's probably the first one: "People responded to Earth Day with letters..."
Since it's more of a detail that supports a fact, it's not as important as the other three.
Answer:n=9
Step-by-step explanation:
Between 8 and 9, but closer to 8 - 8.1 to be exact.