Which statement about controlled experiments is true? a) in a controlled experiment, all variables must be kept the same b) controlled experiments cannot be conducted on living things c) a controlled experiment only tests one variable at a time d) scientists always utilize controlled experiments

Can bacteria reproduce in a way such that when you start out with two bacteria, you get five bacteria? why or why not? * a. yes, because bacteria reproduce sexually, and can produce any number of offspring, just as humans do. b. no, because bacteria grow at an exponential rate. c. no, because when bacteria reproduce, they split into two parts, and two bacteria splitting would result in four bacteria.

Is a measure of the different types of organisms in a community. question options: tertiary secondary primary none of the above

Which of the following best describes the purpose of the parathyroid hormone? a. it decreases the blood calcium level and decreases blood phosphorus level. b. it decreases the blood calcium level and increases the blood phosphorus level. c. it increases the blood calcium level and increases blood phosphorus level. d. it increases the blood calcium level and decreases blood phosphorus level.