Walter and Luis Alvarez hypothesized that an asteroid impact caused the formation of a 66-million-year-old
layer of clay containing high levels of iridium. How did
geologists test this hypothesis? What evidence did they
look for?

what are the options

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.

the atmospheric gas that forms a mild acid when dissolved in water is called carbon dioxide. the correct answer is a. 2.) chemical weathering would cause an inscription on a marble headstone to become harder and harder to read over time.