How would results vary between observing a population directly as opposed to observing them indirectly?

Direct observations are made on subjects by recording the behaviours they exhibit in their natural setting. The researcher can either be physically present to record these observations using a camera or can hide to avoid any interference in the data gathering process. Example, watching or recording a bird chirp.

Indirect observation involves recording the traces left by the subject to understand the reason behind the behaviours exhibited by a subject. Example,    observing the distribution of bird droppings to figure out their movement.

Thus, a direct observation will help identify the behaviours in a population and an indirect observation will establish the reason behind the observed behaviours in the population.

a. as the temperature increases, the kinetic energy of the gas molecules increases & the molecules move faster & further away from each other.

b. if you decrease the temperature of a fixed amount of gas at constant pressure, the combined gas law reduces to charles's law. in this case, volume will also decrease.