Refers to those who volunteer and donate to help treat and work that is useful to people and society voluntarily, without hope of return for cash or any other thing. The yield that a volunteer is fun.
Refers to the voluntary and volunteer work to help the healing and beneficial to the people and society. Voluntarily without expecting remuneration. Or something else? Returns volunteers receive is joy.
Mean, who voluntarily and volunteered to help heal and working as a useful to people and society. Voluntarily without reward money or anything else. Return volunteers are happy.