Which statement best. describes the fossil record?
it is a complete record
it is an incomplete record
most fossils are older than 5. billion years
all fossils are younger than 600 years

Factors that can increase mutation rates a. high temps b. low temps c. food additives d. uv rays

What do isotopes of uranium have the same number of? what do they have a different number of? a) same number of protons; different number of electrons b) same number of protons; different number of neutrons c) same number of electrons; different number of protons d) same number of neutrons; different number of protons

18. which statement about cancer is true?