When is it necessary for a scientists to do research?

select all that apply.

a. before forming a hypothesis

b. only after a hypothesis is written

c. after generating an idea from an observation

d. when designing an experiment to test a hypothesis

A. before forming a hypothesis

C. after generating an idea from an observation

D. when designing an experiment to test a hypothesis

Explanation:

A. before forming a hypothesis: A background research of the previous research studies as well as the literature review is to be done before constructing a hypothesis.

C. after generating an idea from an observation:  After generating an idea from the observation other methodology should be implemented so as to rectified the fact that the observation is correct.

D. when designing an experiment to test a hypothesis: While implementing a suitable scientific methodology a research is required to be done so as test the hypothesis by an accurate and valid procedure.  

answer:

the reaction is type of combination reaction.

explanation:

on the product side, there are 2 molecules of bonded to fe   which means one atom of fe are combined two molecules of . so, balanced chemical equation becomes :

this reaction follows the reaction type of combination reaction. a combination reaction is defined as chemical reaction in which reactants combines together to form a single product.