Question

question 3a: explain why a solar eclipse cannot be seen everywhere on earth. question 3b: total solar eclipses occur every year. why have most people never seen a total solar eclipse?

Explanation:

For 3a: A solar eclipse occurs when the Moon casts a shadow on Earth. The shadow is not large enough to cover the whole planet. Only areas within the umbra (total - eclipse zone) and penumbra (partial - eclipse zone) can see it.
For 3b: Although total solar eclipses occur annually, the path of totality (where the total eclipse is visible) is a narrow strip on Earth's surface. Most people live outside this path, so they have never seen one.

Answer:

Question 3a: The Moon's shadow during a solar - eclipse is not large enough to cover the entire Earth. Only areas in the umbra and penumbra can see it.
Question 3b: The path of totality for total solar eclipses is a narrow strip on Earth. Most people live outside this path.