Every food chain starts with energy from the sun. Green plants are autotrophs, which means they make their food using a chemical reaction called photosynthesis.

According to Lindeman's 10% law, only 10% of energy is transferred from one trophic level to the next.

The flow of energy is unidirectional. After use in metabolic processes, the remaining energy is lost to the environment as heat (according to thermodynamic laws).

Oxides of sulfur (like $SO_2$) present in the atmosphere dissolve in rainwater to form sulfuric acid ($H_2SO_4$), which makes the rainwater acidic.

The biosphere is made up of various ecosystems, therefore the ecosystem is considered the smallest unit of the biosphere.

As per the question, the answer is (2). Scientifically, Chlorofluorocarbons (CFCs) consist of carbon, fluorine, and chlorine, and they typically do not contain hydrogen (H).

The most effective way to control global warming is to reduce the emission of greenhouse gases.

The term Biodiversity was first coined by W. G. Rosen in 1985.

Primary consumers are organisms that eat producers (like green plants) directly, hence they are called herbivores.

Biodiversity refers to the variety of life on Earth, including all types of animals, birds, microorganisms, and plants.

The Indian Parliament amended the Indian Forest Act 1927 and implemented the Indian Forest (Amendment) Act 2017, under which bamboo grown in non-forest areas was excluded from the definition of trees.

Approximately 50 percent of total solar radiation is Photosynthetically Active Radiation (PAR), of which only 2-10 percent is absorbed by plants.

Decomposers break down dead organic matter into simple inorganic substances. In aquatic ecosystems, bacteria and fungi primarily act as decomposers.

Proteins are made of key elements like carbon, nitrogen, hydrogen, and oxygen. Nitrogen is essential for plants for protein synthesis.

Acid rain is primarily caused by an excess of sulfur dioxide ($SO_2$) and nitrogen oxides (like $NO_2$) in the atmosphere. These react with water vapor in the air to form sulfuric acid ($H_2SO_4$) and nitric acid ($HNO_3$).

Forests have the highest biomass because they have a large number and density of big trees.

The Kyoto Protocol is linked to the United Nations Framework Convention on Climate Change (UNFCCC).

Any undesirable physical, chemical, or biological change in the environment is called pollution.

Trees and plants release oxygen gas through the process of photosynthesis. If vegetation is finished on Earth, there will be a shortage of oxygen.

The major endangered organisms have been classified into six main categories by I.U.C.N. (International Union for Conservation of Nature).