The possessive form is backpack's. Example sentence:
My backpack's shoulder strap is broken.
The possessive form for the singular noun backpack is backpack's.Example: My backpack's strap is broken.
No, backpack is a singular, common, concrete, compound noun.
The possessive form for the singular noun backpack is backpack's.Example: My backpack's strap is broken.
The possessive singular noun is explorer's. The possessive plural noun is explorers'.
The possessive form for the noun coyote is coyote's.
The possessive form of zoo is zoo's.
The possessive form for the noun preacher is preacher's.
The possessive form for the noun laboratory is laboratory's.
No, he is not possessive. The possessive form would be his.
The possessive form for the noun oxygen is oxygen's.
The possessive form is grandson's.
The possessive form is island's.