A
not every expirement has control
First, we need to know what's the gravity value in the moon. it is 1.622 m/ s2
to find the force, let's recall this formula----> Force= mass x gravity
force= 83 kg x 1.622= 134.6
A is the closest choice.
He could be blindfolded and know which was his and which was his sister's. All he would need to do is pick them both up and if they were too big then pick them up one at a time. The lumber might make it harder to tell, but this is a question about physical properties.
So there is a change in mass which for the purpose of this question should be quite different. His sister's ought to be much lighter than his. He would find it easier to pick up.
the answer would be winter because the north would be facing away from the son therefor making the northern states cold.