as temperature in the environment increases , the body temperature of a reptile in that environment will increase & as temperature during the day increases , the temperature in an environment will increase ->  as the temperature during the day increases, the body temperature of a reptile in a given environment will increase  reptiles become more active as the day gets warmer & warmer means greater / higher in temperature / warmth ->  reptiles become more active as the day gets warmer in temperature  temperature is a measure of heat energy & warmer means greater / higher in temperature ->  warmer temperatures means greater heat energy  warmer temperatures means greater heat energy & being active requires energy ->  being active requires a warmer temperature  reptiles become more active as the day gets warmer in temperature & being active requires a warmer temperature ->  warmer temperatures cause reptiles to become more active  as the temperature during the day increases, the body temperature of a reptile in a given environment will increase & warmer temperatures cause reptiles to become more active -> reptiles become more active on warmer days because their body temperature increases along with the temperature of their environment