In an acid-base titration, a. acid is always added to the base.
b. acid is never added to base.
c. base is always added to acid.
d. base is added to acid or acid is added to base.

a. acid is always added to the base.

Explanation:

An acid-base titration is a laboratory experiment carried out to determine the unknown concentration of a base or acid by method of neutralization. Neutralization is the reaction between an acid and a base.

In the experiment set-up, the known concentration of acid is placed in the BURETTE while the base is pipetted into a conical flask. The acid is gradually added to the base, which contains an indicator, until a color change is observed. Hence, acid is always added to the base in an acid-base titration.

what is the general relationship between a galaxy's distance from earth and its speed?

the answer is:

the farther away a galaxy is from us, the faster it is moving away from us.