What of the following best defines a notochord?

A. A component that eventually develops into the spinal cord
B. A length of cartilage extending along the body, which will become part of the spinal discs.
C. That which will become the pharynx, gills, or other feeding system in the animal.
D. A muscular tail extending behind the anus.
E. A groove located in the underside of the pharynx that produces mucus in filter-feeding species

B

A species of desert plant secretes a chemical into the surrounding soil that kills seeds from any other species of plant that attempts to germinate in that area. What is this an example of?

A. Commensalism
B. Allelopathy
C. Exploitation competition
D. Apparent competition
E. Intraspecific competition

B

A scientist wants to detach a peripheral membrane protein from the exterior of a cell membrane. Which is the best method to do so?

A. change the salt concentrations
B. perform a light centrifuge
C. add a detergent
D. Change the temperature of the solution
E. Run a small current through the solution

A

All of the following hormones are derived from cholesterol EXCEPT one. Which one is the EXCEPTION?

A. Aldosterone
B. Cortisol
C. Epinephrine
D. Testosterone
E. Progesterone

C