a ruler and a balance a ruler and a microscope a balance and a stopwatch a microscope and a magnet
I gave my students this multiple choice question: Which tools are needed to measure the length and mass of a seashell?

Only one answer is correct among these 4 choices:
- a ruler and a balance
- a ruler and a microscope
- a balance and a stopwatch
- a microscope and a magnet

Could you tell me which one is correct?

a ruler and a balance