Which of these characteristics added most to vertebrate success in relatively dry environments?

A) the shelled, amniotic egg
B) the ability to maintain a constant body temperature
C) two pairs of appendages
D) a four-chambered heart


A

Biology & Microbiology

You might also like to view...

A 26-year-old woman has an odorous vaginal discharge, lower abdominal pain, and difficulty urinating. Vaginal secretions are collected and sent to the laboratory for examination 3 hours af-ter collection. No motile organisms are observed on the wet preparation; however, T. vaginalis is suspected. Which one of the following statements explains this discrepancy?

a. The infection is most likely bacterial; therefore a Gram stain should have been performed. b. The specimen should have been refrige-rated before examination; consequently, the organism was compromised. c. The time between collection and the mi-croscopic examination was prolonged, resulting in loss of motility. d. No discrepancy is present; this organism in nonmotile.

Biology & Microbiology

The term ____________________ refers to the relaxation phase of the cardiac cycle. Fill in the blank(s) with the appropriate word(s)

Biology & Microbiology

________ is the use of genes for treating human genetic disorders

A) Genetics B) Genomics C) Pharmacogenomics D) Gene therapy E) Recombinant DNA technology

Biology & Microbiology

As an adult human ages, the blood vessels lose their elasticity, and blood pressure drops as dilation occurs

Indicate whether the statement is true or false

Biology & Microbiology