You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.
--------
Question: Category: JOHN/PAUL 
Clue: Paul wrote this paean to Soviet women while in India with the Maharishi Mahesh Yogi

Answer: "back in the u.s.s.r."


Question: Category: FROM HERE TO MATERNITY 
Clue: This French doctor called his childbirth preparation method psychoprophylaxis:  mental prevention

Answer: fernand lamaze


Question: Category: ROCKS & MINERALS 
Clue: Scoria, a dark, glassy rock created from this, is heavier than pumice & has bigger holes

Answer:
lava