Question

scientists recently discovered a partial fossil of a dinosaur species called rexoraptor. they are trying to figure out where rexoraptor fits on the dinosaur family tree—specifically, how closely it may be related to modern birds or other theropods. the fossil is incomplete, missing important parts like the skull and feathers, and no dna has been recovered yet.

1. what type of evidence would be most useful in helping scientists better understand rexoraptor’s evolutionary placement?

a. the color of the fossil
b. fossils of fish from the same time period
c. more complete rexoraptor fossils, especially the skull or feathers
d. the age of nearby rocks

1. why would dna evidence help scientists with this investigation?

a. it would tell them how old rexoraptor is compared with other animals
b. it could be compared with dna from other animals to find similarities
c. it would show what rexoraptor looked like
d. it would reveal the fossil’s location

1. what could scientists learn by finding similar rexoraptor fossils in other regions of the world?

a. whether rexoraptor could fly
b. whether rexoraptor lived during the ice age and had special traits
c. whether rexoraptor’s traits were common or unique
d. whether rexoraptor was the fastest dinosaur

Explanation:

Question 6

To determine the most useful evidence for Rexoraptor’s evolutionary placement, we analyze each option:

• Option A: Fossil color is irrelevant to evolutionary relationships.
• Option B: Fish fossils from the same time period don’t relate to Rexoraptor’s evolution.
• Option C: More complete fossils (especially skull/feathers) would provide anatomical details to compare with other dinosaurs/birds, aiding in evolutionary placement.
• Option D: Rock age tells time period but not evolutionary relationships.

To determine how DNA helps, we analyze each option:

• Option A: DNA doesn’t directly indicate age relative to other animals.
• Option B: Comparing Rexoraptor’s DNA with other animals’ DNA reveals genetic similarities, which show evolutionary relationships.
• Option C: DNA doesn’t show physical appearance.
• Option D: DNA doesn’t reveal fossil location.

To determine what scientists learn from similar fossils in other regions:

• Option A: Fossil location/quantity doesn’t indicate flight ability.
• Option B: Rexoraptor is a dinosaur; the Ice Age postdates dinosaurs, so this is invalid.
• Option C: Finding similar fossils in other regions shows if traits are widespread (common) or limited to one area (unique).
• Option D: Fossil distribution doesn’t indicate speed.

Answer:

C. More complete Rexoraptor fossils, especially the skull or feathers

Question 7