The ranges of the red-legged frog and the yellow-legged frog overlap in California. The red-legged frog (Rana aurora) breeding season lasts from January to March. The closely related yellow-legged frog (Rana boylii) breeds from late March through May. What type of reproductive isolating mechanism is mainly responsible for keeping these two species separate?

Scientists developed the ________ model after their studies of the fossil record revealed that some species appear quite suddenly and then remain essentially unchanged phenotypically for a long period of time.

Which of the following lists best describes the features used to classify an organism as a member of domain Bacteria?

In cladistics, ________ is(are) the primary criterion used to classify organisms.

Which piece of evidence would best support the theory of continental drift?

One of the long, branching filaments that collectively make up the mycelium of a fungus is called a(n)

All of the following are milestones in the evolution of plants EXCEPT

Your roommate has heartburn and you hand them a bottle of antacids. They want you to explain how the antacids will make them feel better. What do you tell them?

Which of the following is NOT true regarding Antonie van Leeuwenhoek?

The electrons are unequally shared in_____, and transferred in_____.