Spontaneous generation is the idea that a living thing can arise from nonliving material. this idea was a prevailing theory up until the late 1700s. what most likely caused this theory to be discarded? a. a series of experiments showed that living things only arise when other living things reproduce b. a series of experiments showed that nonliving materials are covered in microorganisms c. ideas in the late 1700s became old-fashioned and scientists looked for new, fresh ideas d. research in the field of biology proved that most living things reproduce sexually