“Dog is Man’s best friend”, or so the saying __________. (Fill in the blank with the correct word)

• goes

• theory

• buried

• affect

We know that wolves are the ancestors of dogs, but researchers can’t agree on a __________ about when canines __________ first tamed.

• theory, were

• fact, are

• story, is

• plan, was

Some scientists think that this __________ happened once, between 20,000 and 40,000 years ago.

• probably

• always

• never

• rarely

Archaeologists study the past by looking at __________ objects found __________ in the ground.

• physical, buried

• digital, floating

• imaginary, flying

• chemical, dissolved

Geneticists explore how genes (codes that are contained in living cells) __________ living things.

• affect

• ignore

• paint

• destroy

They tend to __________ about where dogs came from.

• disagree

• agree

• wonder

• write

Researchers are still not __________ about the details.

• certain

• happy

• confused

• excited

__________ what happened has been difficult because of contradictory or incomplete evidence.

• Establishing

• Establish

• Established

• Establishment

A 14,700-year-old jawbone is the oldest __________ fossil from a domesticated dog, but dog-like remains date back as far as 35,000 years ago.

• definite

• possible

• ancient

• modern

Where is the evidence to __________ what actually happened?

• identify

• ignore

• confuse

• forget