Difference threshold is a minimum alteration in sensory intensity that is noticeable to an observer and can be coded into neural messages. Different threshold is the lowest level of encouragement that is essential to sense that a modification has happened the difference in the intensity between two stimuli that is necessary to yield a just notable difference also known as JND. The just notable difference depends not only on the intensity of the new stimulus but also on the level of stimulation already present which is the more intense the existing stimulus the larger the change must be to be noticeable.
Answer: C
Explanation: The process that occurred in the lake is natural selection. In the presence of an external environmental influence such as pollution, only the trouts that were fit to survive or in other words those that have the alleles that help in adapting to the new conditions live and increased in numbers. In such a case, one can say the fittest of the organisms survived and the corresponding allelic frequency in that population increased over time. The organisms carrying the other alleles died due to pollution and hence the overall frequency of alleles change.
Answer: Yes they are
Explanation: plz mark brainliest