Question

Oxygen liberated during photosynthesis comes from
A. Water
B. Chlorophyll
C. Carbon Dioxide
D. Glucose

Answer 1

Hint:
The word Photosynthesis is a combination of two words photo (light) and synthesis (to make). The process by which green plants make their own food by using carbon dioxide and water in presence of sunlight and chlorophyll by releasing excess oxygen and making carbohydrates is called Photosynthesis. It takes place inside the chloroplasts.

Complete answer:
$6CO_2 + 6H_2O \to C_6H_{12}O_6 + 6O_2$
Complete step by step answer: The process of photosynthesis consists of the reactants and the final products in which one of the most essential reactants is water ($H_2O$). Six molecules of carbon dioxide ($CO_2$) and six molecules of water ($H_2O$) react to form one molecule of glucose ($C_6H_{12}O_6$) and six molecules of oxygen ($O_2$). Photolysis occurs in the light reaction thereby causing water molecules to split up into $H^+ $ and $OH^- $ ions and these $OH^- $ ions react to liberate oxygen.
Green plants possess a green pigment responsible for trapping the sunlight to provide energy for photosynthesis. This pigment then combines the ($CO_2$) and ($H_2O$) to form sugars. Leaves with more chlorophyll have better light absorption.
We exhale carbon dioxide but plants take this carbon dioxide from the air and use it in this vital food making process. Carbon dioxide is another essential reactant which combines with water to form the glucose ($C_6H_{12}O_6$). It enters the plant through tiny holes, leaves, flowers, branches etc.
In photosynthesis the end product is glucose ($C_6H_{12}O_6$) which is used by the plants for energy and it also makes starch and cellulose. Respiration in plants occurs when glucose is produced along with oxygen which is liberated by the splitting of the water molecules. ATP is synthesised from glucose during respiration.

Hence option A is the correct answer.

Note: We cannot imagine our lives without oxygen and thus photosynthesis is extremely vital as it is the primary source of energy and for the oxygen produced is the key to respiration being one of the important life processes. Lesser number of trees will lead to lesser amount of photosynthesis resulting in low amount of oxygen so we should save our environment by planting more trees and preventing deforestation. Plants being autotrophs initiates the food chain being the primary source of food in our ecosystem.