When scientists study organisms in nature (i.e. outside of the laboratory), carefully controlled experimentation is not always possible.  In a case involving mating behavior of birds, data might be gathered by

The first stage in the gametophyte generation is  _____.

Considering that the scientific method includes making observations, formulating a hypothesis to explain the observations, testing the hypothesis with experimentation, analyzing data from experiments, and drawing conclusions about the meaning of the data, which of the following statements about a species of flowering plant represents an experiment?

*Adult echinoderms display radial symmetry. What evidence suggests that echinoderm ancestors evolved from bilaterally symmetrical ancestors?

The closest extant relative of the Tyrannosaurus rex is the _____

What features of charophytes provides evidence for charophytes being the closests relative to land plants?

Which ecosystem would be least affected if sunlight did not reach the Earth for an extended period of time?

The lungs and heart are located in the _____.

In a study locality, rabbits are the only prey of coyotes.  Biologists estimated the population sizes of rabbits and coyotes each year for 5 years and the data are shown in the table below.  Interpret these data about predator/prey relationships.    

Two of Darwin’s finches display a character displacement when they occur as sympatric species. Which of the statements correctly interprets the graph?