A is right because I took the test
Answer:
From the movement of sunspots, Galileo discovered that sun rotate s on its own axis.
Explanation:
All the sunspots are traveling across the Sun's head. This movement is part of the Sun's general rotation of its axis. Observations also suggest that the Sun does not rotate like a solid body, but rotates differently because it is a gas. Actually the Sun is spinning faster at its equator than at at its poles. The Sun rotates once every 24 days at its equator, but only once every 35 days at its poles. We learn this by observing the movement of sunspots and other solar features pass through the Sun.
Answer:

Explanation:
Power is defined as the energy produced (E) per unit of time (t):

This means that the energy produced in the Sun each second (1 s), given the power
, is

Each p-p chain reaction produces an amount of energy of

in order to get the total number of p-p chain reactions per second, we need to divide the total energy produced per second by the energy produced by each reaction:

A conducting material conducts or allows electricity to flow, while an insulator does not allow electricity to flow. For example think of a water pipe, if the pipe has a hole water can flow, on the other hand if it is just a solid rod, no water can flow through. I hope this helps.
Look up pulleys problem through Khan academy and a video should pop up with a problem similar and you should be able to walk through it .