Look at the first sentence of the passage.
Dogs have provided many services for people over the years.
What relationship does this sentence have with the rest of the first paragraph?
A It introduces a problem. The rest of the paragraph lists possible solutions.
B It states an observed effect. The rest of the paragraph examines causes.
C It provides an opinion. The rest of the paragraph provides reasons.
D It presents an idea. The rest of the paragraph gives examples.