Validity generally refers to how accurate a conclusion, measurement, or concept corresponds to what's being tested.
2 you can rule all the others out as they aren't proper questions as they are lacking description
Rowdily is a noisy disturbance so b) loudly
<span>The sentence that is missing an apostrophe for a contraction : (9) Sadly, even after that water is found, only some of its clean and safe enough to drink.The apostrophe must be used with the word 'its' making a verb to be 'it's' out of it. The initial form of a verb makes it be a possessive pronoun, but it does not fit in this sentence. It's is contracted form of 'It is' which is always must stand before an adjective.</span>