Q1: In septic tanks, decomposition of organic bacteria, is done by

ANS:A - anaerobic bacteria

In septic tanks, the decomposition of organic matter is primarily done by anaerobic bacteria. Anaerobic bacteria are microorganisms that can break down organic materials in the absence of oxygen. In the oxygen-deprived environment of a septic tank, anaerobic bacteria thrive and decompose the organic matter present in the wastewater, converting it into simpler compounds such as methane, carbon dioxide, and other byproducts. While aerobic bacteria require oxygen to decompose organic matter efficiently, they are not the primary decomposers in septic tanks due to the lack of oxygen-rich conditions. So, the correct answer is: anaerobic bacteria. They are responsible for the majority of organic decomposition in septic tanks.