The evolution of the tetrapods-four-legged vertebrates occurred in which of the following this geological time periods?

What is the conversion factor between kg/m^3 and g/m^3. express your experimental values for the densities in kg/m^3.

The a metal retainer that keeps the rolling elements evenly spaced. n a. seal n b. separator n c. bearing n d outer race

5g of ammonium nitrate was dissolved in 60g of water in an insulated container. the temperature at the start of the reaction was 23.0°c and at the end it was 19.0°c. calculate the energy absorbed by the reaction.