Which type of sentence is this?
tooth enamel—the hardest substance in the human body—doesn't consist of living tissue, so it can't regenerate itself if it is damaged.

a. simple compound complex
b. compound-complex

According to the 2008 u.s. census, california had a population of approximately 4 × 10^7 people and florida had a population of approximately 2 × 10^7 people. which of the following is true? a. the population of california was approximately two times the population of florida. b. the population of florida was approximately twenty times the population of california. c. the population of florida was approximately two times the population of california. d. the population of california was approximately twenty times the population of florida.