What is the longest age of life on Earth at over 4 billion years? A. Cambrian
B. Precambrian
C. Paleozoic
D. none of the above

Does the sun release radiant energy?

Which statement about the immune system is false? a. lymphocytes reduce inflammation, b. b cells remember specific pathogens. c. most white blood cells kill bacteria d. white blood cells are made in lymph nodes.

All individuals have two alleles for a given trait. according to mendel's these alleles are passed down one each from both mother and father.