Which one of the following animals have air sacs attached to their lungs? A) birds
B) amphibians
C) reptiles
D) mammals
E) all of the above

Which sequence correctly shows the path of carbon dioxide during repiration?

Sea stars, sea urchins, sand dollars, and brittle stars are all memeber of a group, what is the common name of the group they are all in

Plz ! a scientist wants to produce a cow that makes a particular human protein in it’s milk the desired protein causes blood to clot and can be used to treat hemophilia (a blood clotting disorder). which of the following would be best for the scientist to use? a. genetic crosses. b. cloning. c. selective breeding. d. genetic engineering.