crossing over, process in genetics by which the two chromosomes of a homologous pair exchange equal segments with each other. Crossing over occurs in the first division of meiosis. At that stage each chromosome has replicated into two strands called sister chromatids.
B.obtener energia, reproducirise y eliminar desechos
Convection : Warm air rises and cold air sinks, you have a cycle there :D
You can experience it on the beach shore. Since water has a high heat capacity ( it takes longer to heat up ) and the sand get hot quickly, the air on the shore gets warm and rises. When the air reaches to certain elevation (or meet the temperature of the beach), it gets cooler and sinks, cold air from the beach blown to the shore.
the animals that where living there don't have the trees to help them live and don't give them the food that the trees gave them.
