The Living World 8th Edition by George Johnson

تمرين 15

Paleontologists divide the earth's past into the following hierarchical organization, beginning with the largest block of time:
A) age, era, period, epoch.
B) era, period, epoch, age.
C) epoch, age, era, period.
D) period, epoch, age, era.
Of the animal phyla, the only two to successfully populate terrestrial habitats in large numbers of species and individuals are the
A) arthropods and the segmented worms.
B) sponges and the chordates.
C) cnidarians and the arthropods.
D) arthropods and the chordates.
In the Paleozoic era, the first vertebrates to live on land were the
A) amphibians.
B) reptiles.
C) birds.
D) mammals.