Does anyone know the answer to this been struggling for a while

Which of the following is one of the innovations that neolithic farmers become more productive? a) plow b) windmill c) tractor d) reaper

Micah is studying child behavior in playgrounds throughout the world. he wants to see how the children react when teachers select the same child to be the first to use each piece of equipment. which approach is micah is using?

Consultant: you're welcome. as a first step, our team analyzed the other potential primary contenders. the reality is that with such a strong field, it is going to be difficult to gain the of votes necessary to avoid a runoff—unless you want to go negative from the start. and our opposition research team found plenty of ammunition to do just that.