Answer: It is called a Crookes Tube, and he used it to discover cathode rays, which were later determined to be electrons.
Answer:
I think the answers are... b, d, and maybe a. I don't know for sure. So only put these answers in if you trust me!
Explanation:
I had this very question, and I put in what I think were the answers.
Knees and elbows are two of the most common ones.
It’s d like 100000000% trust me