Discuss sea floor spreading. Explain what is happening at the Mid-Ocean Ridge and subduction zones. I need at least 1 paragraph at least 5 sentences.

Which of the following will not cause mass extinction? a. drastic change is weather b. geological change c. both a and b d. none of the above

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.

All annelids and arthropods have a blank body plan . unlike annelids, arthropods also have blank . the circulatory system of annelids is blank , while circulatory system of arthropods is blank .