Which of the following describes an advantage that secondary sources have over primary sources for historians

you did not include the choices, but heres a advantage:

usually research is already done, so it proves that it is able to do research on, therefore the historian can carry out more research.  

Explanation:

whose power in the senate is equal to the power of the speaker of the house?

the answer to fill in the blank in this question would be the word resource, it is defined as the money, material or people (since human resource is a very valuable good) that a company or a person has at disposition (meaning they can use the resource as they see fit), to be able to complete a task or achieve a goal.