Leaves on cacti and pelvic bones on snakes illustrate which of the following?
a. vestigial structures
b. genetic drifting
c. homologous structures
d. DNA mutation
a. vestigial structures
You might also like to view...
Which of the following animals use air sacs to ventilate its lungs?
a. humans b. birds c. frogs d. reptiles e. horses
In a normal mammalian birth, how does the body guarantee that birth proceeds to completion?
A. Via positive feedback -- stretching of the uterus by the descending fetus induces release of oxytocin from the posterior pituitary causing even stronger uterine contractions. B. Via negative feedback -- stretching of the uterus by the descending fetus induces release of FSH and LH from the posterior pituitary causing even stronger uterine contractions. C. Via positive feedback -- stretching of the uterus by the descending fetus induces release of prolactin from the posterior pituitary causing even stronger uterine contractions. D. Via negative feedback -- stretching of the uterus by the descending fetus induces release of prostaglandins from the posterior pituitary causing weaker uterine contractions.
Although exceptions do exist, which is a distinctively amphibian trait?
A) Juveniles have gills, and adults have lungs. B) Respiration occurs through the skin. C) Skin is smooth with no scales, feathers, or hair. D) All of these are distinctive amphibian traits.
Prokaryotic cells evolved about ________ years ago
Fill in the blank(s) with correct word