The half-life of protactinium-226 is 2 minutes if you started with 20 grams of pa-226 how much do you have after 8 minutes

Pam described two substances which participate in photosynthesis. Substance A: Combines with carbon dioxide to form sugar Substance B: Traps sunlight in green plants Which statement is correct? Substance A is water and Substance B is oxygen.

One gene is masked by another gene and neither of them are expressed.

Which of the following statements about similarities among the inner planets is true 1. Mercury and Mars have the same number of moons. 2. Mercury and Venus have similar atmosphere. 3. Earth and Venus are about the same size. 4.

Which of the following is most easily changed to alter resistance? a. vessel length b. blood viscosity c. vessel diameter d. temperature

Which statement is NOT true about energy? a. energy is neither created nor destroyed b. there are many forms of energy, but they can all be categorized as kinetic or potential c. potential energy is energy in motion d.

By what process do all living organisms grow and repair themselves?

What is the name of the heart's contraction?

Which describes the habitat of a frog?

The size of a population refers to the

An electric current will always follow a. the path of least resistance. b. a path toward the north pole. c. a path toward the south pole. d. the path that leads through insulators.