What is the largest source of oxygen on earth? March 30, 2021 / By Preparation Point / MODEL PAPER 91: ASSISTANT in AGRICULTURE (BS-16) 2018 in the Punjab Agriculture Department Share on WhatsApp Share on Facebook Share on Twitter Share on LinkedInA) Algae B) Tree C) Water D) leaves Share this:TwitterFacebookMoreTelegramWhatsAppLike this:Like Loading... Related Share on WhatsApp Share on Facebook Share on Twitter Share on LinkedIn