Doyle learned that only one side of the moon is ever visible from earth. he wants to investigate how the moon moves around the earth and to understand how this motion causes the phases of the moon. which kind of scientific investigation should he use? development of a model a review of existing work a field study

 Create a model.

Explanation: He should develop a model of the Earth-Moon-Sun system. This will let him clearly see how the Moon must move in order for one of its sides to always face away from the Earth. If he uses a light source for the Sun in his model, it will also show how the phases of the Moon happen. The real Earth-Moon-Sun system is too large for him to observe it in the same way.

kennedy creates personal credibility by saying he is more than fit to lead. he talks about the sixty day period that he constructed administration, and says based on that he will be an acceptable leader.

jfk has a great reputation as an american citizen. he fought in wwii, and earned the navy and marine corps medal. he saved several men on his pt-109 patrol torpedo boat after an attack by the japanese navy. he also served in congress for the 11th congressional district for massachusetts, and served three terms in the house of representatives.

explanation:

halibut, flounder, tuna, and trout are all fish. so your first answer is 1.) fish. and since fish is edible, your next answer would be 3). edible

to describe those fishes more thoroughly, some of those fishes live in fresh water, and some of the fishes live in salt water, and that is not a thing that they all have in common. the question is asking what is common with all of the fish, so answer choices 2). fresh water and 4). salt water are not right.