Barbiturates and benzodiazepine drugs bind to GABA receptors to open chloride channels, inhibit neural impulse, and induce tranquility.
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Scientists have learned that the Kuna, a tribe of indigenous South Americans, have almost no incidence of hypertension most likely because the Kuna people ____.

A) possess an allele unique to their tribe
B) consume a large amount of cocoa
C) have developed sophisticated medicines
D) exercise unusually often
E) have remarkably narrow blood vessels

Which brain region plays an essential role in the formation of declarative memories?

A) cerebrum
B) cerebellum
C) hippocampus
D) thalamus
E) hypothalamus

In genetics, map units express the distance between

A) chromosomes during metaphase.
B) two loci on a chromosome.
C) alleles.
D) polar bodies.
E) homologous chromosomes.

The knee is an example of a(n)

A) immovable joint.
B) slightly movable joint.
C) fibrous joint.
D) immovable synovial joint.
E) movable synovial joint.

An aphid is an insect that has mouthparts to sip plant sap. When placed on an herbaceous stem, it soon has its mouthparts embedded and is withdrawing plant sap. What layer of cells has the aphid's mouthparts tapped?

A) xylem
B) phloem
C) parenchyma
D) trichomes
E) collenchyma

The sphincter that separates the ileum and the cecum is the ________.

A) ileocecal sphincter
B) pyloric sphincter
C) lower esophageal sphincter
D) anal sphincter

What is in the outer cytoplasmic layer of radiolaria?

A) nucleus
B) contractile vacuoles
C) algae
D) mitochondria
E) gas filled vacuoles

A cleft lip results when

A) the two halves of the secondary palate do not fuse.
B) the frontonasal and maxillary processes do not fuse.
C) the lateral edges of the nasal placodes do not fuse with the maxillary processes.
D) the maxillary processes do not fuse with the mandibular processes.
E) None of the choices are correct.