How might geographic range help explain how some species are able to survive extinction periods? What is the role of background extinction rate in this theory?

Will someone me with this.. specialized cells which perform a particular function form: tissues organs or organism

Scientists are conducting a study on the effectiveness of a new drug on memory loss. they are giving some of the test subjects the new drug to find out if it improves their long-term memory. which are possible limitations of this study? check all that apply. a) test subjects may want to participate in additional experiments. b) test subjects may think they should be paid more. c) test subjects may get bored and want to quit early. d) test subjects may have to travel during the experiment. e) test subjects may have full-time jobs. this is multiple choice. you for the !

Which statement is not an accurate description of meiosis? a) meiosis produces offspring that are genetically diverse. b) meiosis produces offspring that are identical to the parent. c) in sexual reproduction half of the genetic material comes from the father (sperm) and half of the genetic material comes from the mother (egg). d) meiosis decreases the number of chromosomes by half so that when a sperm fertilizes an egg, the resulting zygote has the correct number of chromosomes.