Immediately after gastrulation:

1. The embryo forms a blastula

2. Sperm travel to the oviduct

3. The body axis of the embryo appears

4. The fetus' circulatory system begins to mature

Which of the following is an organic molecule?

True or false: oceanic crust is denser then continental crust because it is comprised of silica.

The vitamin necessary for fibrinogen and prothrombin formation (found in green vegetables and released by intestinal bacteria) is:

What is sulfur dioxide

What is the main cause of competition between two species? A. An overlap in the species' niches B. The extinction of one species C. Genetic drift in both species D. An increase in biodiversity in one species

Some populations of bats live in areas with high levels of noise pollution, such as near heavily trafficked bridges. How might the hunting behavior of bats be affected by such an environment?

Which best describes the relationship between blood flow and lymph flow? A. Blood flows through the contraction of skeletal muscle, and lymph flows through the contraction of cardiac muscle. B.

What is one example of a primary succession

What are biological terms in order from least to greatest

In vertebrates, the speed of transmission along neurons is much faster in myelinated neurons compared to unmyelinated neurons. Which of the following is not true of transmission along myelinated neurons? A.