What is made of a central star around which various other non-star objects orbit?
a) planetary system
b) a nebula
c) a galaxy
d) black hole

Cells tend to have a relatively small and uniform size. why aren’t cells larger?

Which statement describes an endocrine function rather than an exocrine function? a. salivary glands release saliva into the mouth. b. sweat glands release sweat onto the skin c. the pineal gland releases melatonin into the blood. d. esophageal glands release mucus into the esophagus.

Other than earth, is also known to have magnetic pole reversal? a: venus b: mars c: earths moon d: the sun