In German, "die Schere" is the same thing as "(the pair of) scissors" in English (like the one thing you use to cut) except it is actually used singularly in regard to verb conjugations, so "die Scheren" is really multiple pairs of scissors (like in the aisle of a store where you would find a bunch of scissors). It's the same with "die Hose" - "the pants," z.B. "Ich kaufe die Hose" - "I buy the (singular) pair of pants," "Die Hose ist zu kurz" - "The pants are too short."
"Scissors" is a plurale tantum, which is "a noun that has no singular form, such as scissors (in most usage)." Cf. "pants", "trousers", etc.
So in English scissors always takes the plural verb form, which for "to be" is "are". In German--as niceliz explains very well--one makes the distinction both with the conjugation of the verb (e.g., sind vs. ist) and the noun suffix (Scheren vs. Schere). So, the English form of this sentence is ambiguous, and there is only one choice. The German form, however, has two options: "Schere sind" oder "Schere ist".