Acertain radioactive element has a half-life of one hour. if you start with 40.0 grams of the element at noon, how much of the radioactive element will be left at 2 p. m.? (3 points)
0.0 grams
10.0 grams
20.0 grams
5.0 grams

Write the complete balanced equation for the reaction between lead (iv) oxide (pbo2) and water (h2o).

Which term best describes the form sound takes as it travels away from a drum (a- gas)(b-music) ( c-waves) (d-particles

Monkeys and bats have similar bone structure in their forelimbs. however, monkeys have longer forelimbs to use for climbing and swinging in trees. bats have shorter forelimbs to use for flight. which term best describes how monkey and bat forelimbs are related to each other? a. homologous b. embryonic c. analogous d. vestigial