Once again, I had to pause the local news, watch my husband roll his eyes, and snap a picture of this jewel. This is a common mistake because it kind of defies the rules. The possessive of “it” is “its.” The contraction of “it is” is “it’s.” I get that it is confusing, but it’s a concept that can be (and should be) learned. If you are tempted to use the apostrophe, check to make sure it is correct by substituting “it is” for “it’s.” If it doesn’t make sense (and it won’t if it’s supposed to be a possessive), then don’t use the apostrophe. An example is the sentence in this post “. . . but it’s a concept that can be . . ..” You can replace the “it’s” with “it is” in that sentence so it is correct–“. . . but it is a concept that can be . . ..”