What are types of scientific explanation

Which of the following describes the difference in stimuli required to detect a difference between the stimuli? a. just noticeableb. signal detectionc. subliminald. top down

Is genetic diversity the same as genetic variation?

The lineage of pea plants produced round seeds for four generations. the plants that fertilized these pea plants also produced round seeds. however, in the fifth generation, the plant produced to two plants with wrinkled seeds. can that be possible?