If you put an egg on a sidewalk on a hot day in july and try to cook it you are using?
passive solar energy
geothermal energy
active solar energy
biomass

Explanation:

First of all, you must know that you if you put an egg on a sidewalk you are dealing with energy from the Sun, i.e. solar energy, while geothermal energy is energy that comes from the inner of the Earth and biomass energy comes from plant or animal material.

The term passive solar energy refers to the fact that the energy of the sun is used directly for the intended task, which in this case is to cook the egg.

The term active solar energy refers to the fact that the energy of the Sun is converted into a  different form of energy and then used for your purpose. For instance, if the energy of the Sun were used to produce electricity and then this electricity used to cook the egg, you would be using an acitve solar energy.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.