From the brightness of the light of course. If the brightness is increasing it means the the light source is approaching and if the brightness is decreasing it means the light source is leaving.
The main reason why the testes are suspended within the scrotum is to provide cooler temperature for the testes and make it fertile for penetrating the egg. The Scrotum may contract or lengthen depending on the temperature of its surrounding.
In a survivable cold environment, an ectotherm is more likely to survive an extended period of food deprivation than would an equally sized endotherm because the ectotherm is using a little amount of its energy for temperature regulation.<span />
Inferences are related to observations because inferences are an explanation for an observation you have made.
