Much of the research on hallucinogenic drugs such as LSD has focused on the neurotransmitter serotonin, a chemical that when released from a presynaptic serotonin-secreting neuron causes the transmission of a nerve impulse across a synapse to an adjacent postsynaptic, or target, neuron. There are two major reasons for this emphasis. First, it was discovered [...]

If ((t^2)-1)/(t-1)=2, then what value(s) may t have? A) 1 only B) -1 only C) 1 or -1 D) no values E) an infinite number of values

Overindulgence, fatigue and worry are the three —– of civilization that probable do most to ——— the natural defenses of the body. (A) Products —– Sustains (B) Enemies —– Influence (C) Victims —– Damage (D) Delinquents —– Exploit (E) Concomitants —– Undermine

APIARY : BEE (A) museum : painting (B) dam : water (C) arboretum : tree (D) forum : speech (E) planetarium : star

Historians attempting to explain how scientific work was done in the laboratory of the seventeenth-century chemist and natural philosopher Robert Boyle must address a fundamental discrepancy between how such experimentation was actually performed and the seventeenth-century rhetoric describing it. Leaders of the new Royal Society of London in the 1660s insisted that authentic science depended [...]

In prehistoric times brachiopods were one of the most abundant and diverse forms of life on Earth: more than 30,000 species of this clamlike creature have been cataloged from fossil records. Today brachiopods are not as numerous, and existing species are not well studied, partly because neither the animal’s fleshy inner tissue nor its shell [...]

Medieval kingdoms did not become constitutional republics� overnight; on the country the change was —–. (A) Unpopular (B) Unexpected (C) Advantageous (D) Sufficient (E) Gradual

Before 1965 many scientists pictured the circulation of the ocean’s water mass as consisting of large, slow-moving currents, such as the Gulf Stream. That view, based on 100 years of observations made around the globe, produced only a rough approximation of the true circulation. But in the 1950’s and the 1960’s, researchers began to employ [...]

Recently the focus of historical studies of different ethnic groups in the United States has shifted from the transformation of ethnic identity to its preservation. Whereas earlier historians argued that the ethnic identity of various immigrant groups to the United States blended to form an American national character, the new scholarship has focused on the [...]

Until recently many astronomers believed that asteroids travel about the solar system unaccompanied by satellites. These astronomers assumed this because they considered asteroid-satellite systems inherently unstable. Theoreticians could have told them otherwise: even minuscule bodies in the solar system can theoretically have satellites, as long as everything is in proper scale. If a bowling ball [...]

The study of the astronomical practices, celestial lore, mythologies, religions and world-views of all ancient cultures is called archaeoastronomy. It is described, in essence, as the “anthropology of astronomy”, to distinguish it from the “history of astronomy”. Many of the great monuments and ceremonial constructions of early civilizations were astronomically aligned, and two well-known ancient [...]

BEAR : HIBERNATE :: (A) Parrot : Imitate (B) Curator : Conserve (C) Bird : Migrate (D) Prosecutor : accuse (E) Traveler : Locate

What it means to “explain” something in science often comes down to the application of mathematics. Some thinkers hold that mathematics is a kind of language—a systematic contrivance of signs, the criteria for the authority of which are internal coherence, elegance, and depth. The application of such a highly artificial system to the physical world, [...]

plead : suppliant (A) disperse : rioter (B) shun : outcast (C) revere : elder (D) beg : philanthropist (E) translate : interpreter