Under which of these conditions would scientists use the polymerase chain reaction (PCR) before they analyze a DNA sample?

What evidence did mendel find that supported his law of independent assortment? a. dominant traits are expressed when there is a dominant allele. b. traits do not affect the inheritance of other traits. c. some traits have three or four different alleles. d. plants and animals can both reproduce sexually.

What evidence supports the law of conservation of energy? a) mechanical energy is converted to chemical energy during photosynthesis. b) oxygen is made from the breakdown of carbon dioxide during photosynthesis. c)energy is absorbed by chlorophyll and becomes chemical energy during photosynthesis. d)the sun gives off light energy that is absorbed by plants.

Several bird species feed in a certain species of tree. each bird species feeds in a different part of the tree. which statement is true of these bird species? a. they have adapted to different niches due to competition b. they have a carnivorous relationship with the tree species. c. they have adapted to different niches due to predation d. they have a symbiotic relationship with the tree species.