You need to answer a given question containing a blank (_). Your answer must be one of the two objects mentioned in the question, for example "trophy" and "suitcase". Your answer must not contain a word that is not present in the question. Please don't use articles (e.g., the, a) before the answer.

The weightlifter felt a lot more tough when working with barbells than with kettlebells, because the _ worked more complex muscle groups.
barbells

Cutting the wood with the chainsaw proved to be more difficult than the hand saw since the _ 's blades were dull.
chainsaw

John took a sip of the milk and spat it on the food in front of him. The _ is putrid.

milk