13. Sirius which appears bigger than Rigel, is actually very small compared to Rigel.

Why does Sirius appear larger than Rigel? It is because Sirius _________.

A. is closer to us

B. reflects more lights

C. triple its size as it reflects more

D. double its size as it reflects more lights

14. Why can we see different parts of the sky at different times of the year? It is due to the

___________________.

A. rotation of the earth

B. revolution of the earth

C. revolution of the moon

D. tilt of the earth’s axis

15.Which is known as the largest constellation?

A. Pegasus C. Polaris

B. Pisces D. Orion​