If it is in the beginning of a sentence, yes.
The word evolution does not need to be capitalized.
No, coral does not need to be capitalized.
Yes, "Government contract" should be capitalized when it refers to a specific contract involving the government.
Yes. US Government is capitalized.
No, it shouldn't be capitalized.
No, circa does not need to be capitalized.
No, it doesn't need to be capitalized.
No, kinetic energy doesn't need to be capitalized.
Yes, "Home Office" should be capitalized when referring to a specific government department in countries like the UK. However, if it is used more generally to refer to a workspace within one's home, it does not need to be capitalized.
it does not need to be capitilized.
No. Queries do not need to be capitalized.
Usually! If you are referring to a particular group of legislators, (as you probably were), as in "the Senate passed a law yesterday" it is capitalized like a proper name. If you are referring conceptually to the upper house in any republican form of government, no capitalization.