The most abundant elements by mass in the body of a helathy human adult are ; oxygen (61.4% ) ; carbon (22.9 % ) , hydrogen (10.0 %) ; and Nitrogen (2.6 % ). The weight which a 75 kg [person would gain if all 1H atoms are replaced by 2H atoms is hydrogen (10.0 %) ; and Nitrogen (2.6 % ). The weight which a 75 kg [person would gain if all 1H atoms are replaced by 2H atoms is The most abundant elements by mass in the body of a helathy human adult are ; oxygen (61.4% ) ; carbon (22.9 % ) November 25, 2020 Category: Uncategorised (JEE Advanced Physics by BM Sharma + GMP Solutions) , Facebook Messenger WhatsApp Share this:TwitterFacebook Related