Carbon dioxide and oxygen are two molecules that undergo this simple diffusion through the membrane.
Answer:
It is a season in which fish reproduce.
Explanation:
Piracema is not name of the fish, its the name given to the period of the year when fish reproduce within the Paraguay River. The season of reproduction started from October till March, during this period the fish swim upstream to lay their eggs and reproduce. Thus the season is critical for the maintenance of fish populations in the waters of the rivers and lakes. Brazilian states prohibit fishing during this period in order to maintain fish population in the river.
Survival of the strongest... an organisms strength does not affect the natural selection process. Natural selection is adapting the species to be able to better survive in its environment. In order to better survive, an organism does not to be strong. e.g. a plant is probably not a “strong” organism and natural selection doesn’t change that in most cases