Scientists have developed a new type of margarine that contains plant ingredients. They expect that the margarine will lower blood cholesterol levels. They want to test their hypothesis by comparing the blood cholesterol levels of people who will consume the new margarine with those who will consume regular margarine for a few days. Both groups of people will know which type of margarine they are to consume. Which type of research design will the scientists consider

intervention study

Explanation:

The intervention study or research helps to examine the effects of an intervention of an outcome of interest. The main purpose of this type of study is to endenger the desirable of the individuals in need.

Such studies are often prospective.

In the context, scientist who have developed a new margarine containing plant ingredients. The scientists wanted to test the hypothesis whether consuming this new margarine lowers blood cholesterol in the body or not. They gave people to consume the margarine and is doing the research study. Such a research design is called as the intervention study.

explanation:

the fossil record extends back to a dog-like ancestor some 55 million years ago, which gave rise to the first horse-like species 55 to 42 million years ago in the genus eohippus.

i think its the first one