Is it 1) excretory 2) circulatory 3) integumentary 4) digestive 5) nervous 6) respiration

What is thought to have caused the mass extinction at the end of the cretaceous period?

Which of the following statements about archaea and bacteria is true? a. neither is single-celled. b. they both have nuclear membranes. c. neither reproduces by binary fission. d. they both lack a nuclear membrane.

Which of the following are not included as modern mammals that evolved during the eocene epoch? primates artiodactyls perissodactyls none of the above