l23+l24 Q&A
c - (correct answer)Most of the major groups of mammals arose at the end of the
Cretaceous period. This most likely occurred because
a. hair allowed mammals to exploit colder habitats of a changing climate.
b. differentiation of teeth in mammals allowed them to exploit varied diets.
c. the extinction of non-avian dinosaurs opened niches, allowing mammals to diversify.
d. development of a marsupium allowed mammals to easily migrate with their young.
e. increased oxygen levels allowed mammals to become very large.
b - (correct answer)Which trait is unique to mammals?
a. Claws on the digits
b. Secretion of a fluid (milk) from mammary glands
c. Endothermy (internal heat production)
d. Possession of an amniote egg
e. The ability among certain members of the group to fly
d - (correct answer)Which statement about marsupial mammals is true?
a. They are the only egg-laying mammals.
b. Their mammary glands have no nipples.
c. They have no placenta.
d. Gestation is short, and the young complete development outside the uterus in a
special pouch.
e. They are found only in Australia.
a - (correct answer)Which group of living eutherian mammals has the most species?
a. Rodentia (gnawing mammals)
c - (correct answer)Most of the major groups of mammals arose at the end of the
Cretaceous period. This most likely occurred because
a. hair allowed mammals to exploit colder habitats of a changing climate.
b. differentiation of teeth in mammals allowed them to exploit varied diets.
c. the extinction of non-avian dinosaurs opened niches, allowing mammals to diversify.
d. development of a marsupium allowed mammals to easily migrate with their young.
e. increased oxygen levels allowed mammals to become very large.
b - (correct answer)Which trait is unique to mammals?
a. Claws on the digits
b. Secretion of a fluid (milk) from mammary glands
c. Endothermy (internal heat production)
d. Possession of an amniote egg
e. The ability among certain members of the group to fly
d - (correct answer)Which statement about marsupial mammals is true?
a. They are the only egg-laying mammals.
b. Their mammary glands have no nipples.
c. They have no placenta.
d. Gestation is short, and the young complete development outside the uterus in a
special pouch.
e. They are found only in Australia.
a - (correct answer)Which group of living eutherian mammals has the most species?
a. Rodentia (gnawing mammals)
