The ____ of a bird's digestive system contains sand and rocks to aid in mechanical digestion
a. crop
b. esophagus
c. gizzard
d. intestine
e. mouth
ANSWER: c
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Arthropods invaded land about 100 million years before vertebrates did so. This most clearly implies that _____
A) arthropods evolved before vertebrates did B) extant terrestrial arthropods are better adapted to terrestrial life than are extant terrestrial vertebrates C) ancestral arthropods must have been poorly adapted to aquatic life, and thus experienced a selective pressure to invade land D) vertebrates evolved from arthropods E) arthropods have had more time to coevolve with land plants than have vertebrates
Broad, ecologically uniform areas with stable and distinctive collections of species are called ____
Fill in the blank with the appropriate word.
Now extinct, several lineages of ____ appear in the fossil record from the Ordovician through the
Devonian periods. These jawless fishes had skin heavily armored with bony plates and scales, and imprints of some of their fossils indicate that their brains had three regions.
a. acanthodians b. conodonts c. osteolepiforms d. placoderms e. ostracoderms
Amino acids are to proteins as ____ are to carbohydrates
A) nucleic acids B) fatty acids C) monosaccharides D) nucleotides