Why do the DNA fingerprints of non-related individuals differ? 

All animals must get oxygen for respiration.  Which of the following is NOT involved in this critical function?

According to the phylogenetic tree below, modern-day mammals are most closely related to which modern group of reptiles?

Homeostasis in animals can be generally defined as the _____.

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

Evidence suggests that an asteroid struck the Gulf of Mexico near what is now the Yucatan Peninsula about 65 million years ago.  What was likely the cause of the cause of the loss of many plants?

Which organ system plays the least role in maintaining optimal conditions of the animal body? 

The lungs and heart are located in the _____.

Why do viruses only infect specific types of cells?

In the vascular bundles of most dicot stems, primary phloem differentiates toward the ________of the stem, while primary xylem differentiates toward the ________of the stem.