Tickleback evolution lab final quiz 1. how did some ancestral sea-run stickleback populations come to live exclusively in fresh water? these populations swam to freshwater lakes to spawn and then never returned to the ocean because there were fewer predators in lakes. they became trapped in lakes that formed at the end of the last ice age. they don't actually live exclusively in fresh water; they only live in fresh water at certain stages in their lives. they developed traits that made them better adapted to fresh water and, as a result, had to move to a freshwater environment to survive.

i believe the correct answer from the choices listed above is the first option. the scientists need to look at the   validity of data, claims, hypotheses, and observations before  developing an argument. they base their arguments on facts that are present and they make sure they have proofs. 

explanation:

the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.