Question

you have noted an increase in cancer rates among a local harbor seal population. you also noted an increase in the release of toxic, potentially cancer - causing pollutants by industry in the area. you think that the industry is causing the increase in cancer rates. this is a testable idea. what is this sort of testable idea called?
a hypothesis
an observation
an opinion
a prediction

Explanation:

A hypothesis is a testable idea or proposed explanation made on the basis of limited evidence as a starting - point for further investigation. Here, the idea that industry is causing the increase in cancer rates among harbor seals is testable, fitting the definition of a hypothesis. An observation is just noting a fact (like increase in cancer rates or pollutant release), an opinion is a personal belief not necessarily testable, and a prediction is about what will happen in the future.

Answer:

A. A hypothesis