N the Watson-Crick model of DNA, the two strands of the double helix are united by hydrogen bonds between a.
nitrogenous bases

b.
phosphate groups

c.
nitrogen atoms

d.
sugar molecules

The galapagos island contain 13 species of finches four of the species are seen here it is believed that all of the species had one common ancestor and overtime

The sketch shows a rynchosaur, an extinct animal that is known only from fossils. there has been much debate about the classification of these creatures. some scientists suggest that they belong with primitive amphibians, and some think they are related to snakes and lizards. the data equally support both cases. which statement best explains how to draw a cladogram that includes the rynchosaur? draw the cladogram for amphibians. draw the cladogram for reptiles. draw two cladograms, both showing the traits, and leave it as a hypothesis. draw two cladograms, both showing the traits, and have scientists vote

Which of the following was not a major animal on land during the carboniferous period? amphibians insects both a and b none of the above