An advantage of hydraulic systems over pneumatic systems is that they a. provide a gentle, cushioning effect
b. can transfer energy with very little loss of force
c. are slow to respond
d. work well at all temperature ranges.

D: but see below.

Explanation:

There are two main disadvantages to a pneumatic  system

1. They require a compressor of some sort.

2. They can be slow to respond.

That makes car brakes the choice of engineers to be the hydraulic system a far superior choice for automobiles.

A car usually has to stop quickly and efficiently.

A: hydraulic systems generally do not provide a cushioning effect. I would say A is not what you want.

C. Hydraulic systems are quick to respond. The answer is not C

D. Work well at all Temperature ranges. They better do this. A few days ago the outside temperature where I live reached - 40. The summer can reach plus 30 C. That's a range of 70 degrees. They better work over this range.

Unfortunately B is also true. I think you are intended to pick B, but D is also true. Perhaps the    question means a greater range than 70 degrees. If that is so, B is really your better answer.

answer: -

reaction:

na + cl ⇌ nacl

balanced chemical equation:

na + 2cl ⇌ nacl2

sodium + clorine goes to form sodium chloride (table salt).

the product is nacl2.

and the reactants are na and cl.

(note: if you don’t know what ⇌ means, read below: -

⇌(double head arrow) means reversible reaction).