If an isotope starts with 160 grams and 2 half-lives pass, how much is left? A. 80
B. 40
C. 20

What initially causes a nerve impulse? release of enzymes out of the neuron movement of chemicals into the dendrites of the neuron pathogens attacking the dendrites of the neuron red blood cells bathing the neuron

Which hormone is used by both males and female?

Which spheres are involved when sedimentary rocks formed from parts of seashells at the bottom of the ocean? a.) biosphere, atmosphere, geosphereb.) geosphere, hydrosphere, biosphere c.) geosphere, exosphere, hydrosphered.) hydrosphere, biosphere, atmosphere