One scientist kept 20 grams of a radioactive material in a container. What will be the mass of the radioactive material left in the container after 2 half lives?

40 grams
4 grams
10 grams
5 grams

Why is it important to study each branch of earth science?

Which best example best demonstrates the importance of having knowledge of evolutionary relationships? a. illustration of a plant b.organ transplantation between species c. blood donation from a human d. do you need sequence of an insect.

The bacteria inside a tube worm would be analogous to what organism in the ocean ecosystem near the waters surface? a. photosynthetic algae b. shrimp c. clown fish d. parasitic lamprey