1. A biologist was in a forest when he came across a family of squirrels hiding nuts for the winter. The biologist was interested in this behavior, so he stayed and watched the squirrels for a few hours. He recorded what he observed in a notebook. Which of the following explains why this type of research is NOT considered an experiment?

A. The biologist observed the squirrels and did not test variables.
B. The biologist came across the squirrels by chance and had no formal plan.
C. The biologist did not observe the squirrels for long enough to collect data.
D. The biologist did not collect valid data on the different species of squirrels present.

2. For pea plants, T represents a dominant allele for tall pea plants and t is the recessive allele for short pea plants. If two plants with the Tt genotype are crossed, what is the probability that offspring will exhibit the dominant trait?
A. 75%
B. 100%
C. 25%
D. 50%

3. Which statement is true about DNA?

A. DNA is an exact copy from parent to offspring
B. DNA contains genes that hold specific traits for an organism
C. DNA is not necessary for an organism to reproduce
D. Organisms create their own DNA sequence that is not like their parents