Orlah 2.2-2.5

The second parakh discusses many different cases of taruvus, where a prohibited food item is mixed together with a permitted food item, or possibly liquids too.

And we learned in the previous Mishnah that when it comes to if any of those are mixed together with chulin, which is unsanctified produce, then the entire mixture is forbidden unless there is a hundred times more chulin than the forbidden item.

However, when it comes to ola and kleakerem, which are two prohibited items, which not only is it forbidden to eat, but it's also forbidden to benefit from them, and therefore if they are mixed with chulin, you need 200 times more chulin than the forbidden item in order to nullify the forbidden item and to permit the mixture.

Now the following couple of Mishnahis teach us that even a prohibited item can combine with a permitted item in order to nullify a different prohibited item.

As the Mishnah tells us, ha-trummah ma'ales ha-orla, trummah can assist to nullify orla, the ha-orla is ha-trummah and orla can also assist in nullifying trummah.

Meaning, if truma and chulin together make up enough to nullify the ola, or if the ola and the chulin make up enough to nullify the truma in the mixture, then the forbidden item, which makes up the small part, will be nullified, and the mixture will be permitted.