Geographic isolation caused the separation of rainforest frog populations into a population in the
climate became wetter and warmer, causing the rainforest to expand. When males from the north
north and a population in the south. The separated populations later reconnected because the
mated with females from the south, the offspring failed to develop past the tadpole stage. When
males from the south mated with females from the north, the offspring developed more slowly than
the offspring of pairs of northern frogs. Based on these data, which event occurred while the two
populations of frogs were separated?
A. The two populations developed into new species.
B. The two populations mated with other species of frogs.
C. The two populations began a new method of reproduction.
D. The two populations had fewer offspring than before the separation.

How can active reading strategies you? o a. they can you get into better physical shape. o b. they can you read fewer science articles. o c. they can you understand what you read. o d. they can you avoid reading altogether.

Which description provides the best objective summary of the article in the passage?

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.