Weightlessness affects astronauts' bodies by:

  1. making them heavier
  2. stopping their heart
  3. increasing their mass
  4. weakening muscles and bones over long missions
Answer

D) weakening muscles and bones over long missions

Muscles and bones aren't loaded. SLO P-11-B-16 · Understanding

Physics MCQ · More Circular and Rotational Motion MCQs · Practise