A trait that may be co-opted for a new function, such as bird feathers, is called a(n)

A) adaptation.
B) complex adaptation.
C) exaptation.
D) polytomy.

Gram-negative cell walls have an outer membrane that contains lipids and peptidoglycans.

Flower parts are borne on the tip of a stalk referred to as the

A) calyx.
B) corolla.
C) filament.
D) receptacle.
E) stigma.

Which of the following statements if False?

A) Most industrialized, democratic societies ban the use of permanent strike replacements.
B) Employers rely on permanent strike replacements only when the economic conditions warrant their use.
C) Employers sometimes intentionally push unions to a strike so they can hire permanent replacements.
D) A business could be kept open using temporary, rather than permanent strike replacements in most instances.

Parathyroid hormone functions to increase calcium ion levels in blood. If its secretion is regulated through negative feedback, under which conditions would this hormone normally be released?

A) Parathyroid hormone secretion occurs when blood calcium levels are too low.
B) Parathyroid hormone secretion occurs when blood calcium levels are too high.
C) Parathyroid secretion is constant to maintain blood calcium levels.
D) Parathyroid hormone secretion increases in the morning and decreases in the afternoon.

HIV attacks

A) helper T cells.
B) Sertoli cells.
C) B lymphocytes.
D) interstitial cells.
E) follicle cells.

A nerve impulse is caused by

A) the movement of a sodium ion all the way from dendrite to axon tip.
B) the movement of a potassium ion all the way from dendrite to axon tip.
C) the movement of sodium ions from a dendrite to an axon tip and the movement of potassium ions from the an axon tip to a dendrite.
D) a change in the difference in positive and negative ions on the outer and inner surfaces of the neuron membrane, a change that opens adjacent channels and propagates its flow.
E) a change in the difference in sugar molecules on the outer and inner surfaces of the neuron membrane that opens adjacent channels.

Which term refers to the study of the patterns in the distribution of plants and animals around the world?

A) natural selection
B) biogeography
C) ecology
D) archaeology
E) comparative morphology

Wood is composed of

A) cork.
B) cork cambium.
C) secondary phloem.
D) secondary xylem.
E) sieve-tube members.

If L=load, F=fulcrum, and AF=applied force, what type of lever system is described as LAFF?

A) third-class lever system
B) second-class lever system
C) fourth-class lever system
D) first-class lever system