Option A is correct becose pollution can chaing the biological equilibrium..

Loss of relative biological equilibrium refers to a disruption or imbalance in the natural balance and functioning of ecosystems. This can be caused by various factors, including pollution, radiation, high temperature, and low temperature. However, in this case, the correct answer is option 'A', which is pollution. Let's explore why pollution can lead to the loss of relative biological equilibrium in more detail.

Effects of Pollution on Biological Equilibrium:

1. Pollution disrupts the balance of ecosystems:
- Pollution, such as the release of toxic chemicals into the environment, can have detrimental effects on various organisms within an ecosystem.
- It can lead to the decline or extinction of certain species, disrupting the natural balance and interdependence of different organisms.

2. Water pollution:
- Water pollution caused by the discharge of industrial waste, agricultural runoff, or improper sewage treatment can result in the contamination of water bodies.
- This contamination can harm aquatic organisms, including fish, amphibians, and invertebrates, disrupting the food chain and overall ecosystem functioning.

3. Air pollution:
- Air pollution caused by the emission of pollutants from industries, vehicles, and burning of fossil fuels can have severe consequences for both terrestrial and aquatic ecosystems.
- Pollutants like sulfur dioxide and nitrogen oxides can cause acid rain, which can acidify soils and bodies of water, negatively impacting plants, animals, and microorganisms.

4. Soil pollution:
- Soil pollution can occur due to the accumulation of chemicals like heavy metals, pesticides, and industrial waste.
- These pollutants can leach into the soil, affecting the growth and health of plants, as well as the organisms that depend on them.

5. Bioaccumulation and biomagnification:
- Pollutants can accumulate in the tissues of organisms through processes like bioaccumulation and biomagnification.
- As pollutants move up the food chain, their concentrations increase, leading to toxic effects on higher trophic levels, including humans.

6. Disruption of ecological processes:
- Pollution can disrupt important ecological processes like nutrient cycling, energy flow, and reproduction.
- This disruption can have cascading effects on the entire ecosystem, leading to a loss of relative biological equilibrium.

In conclusion, pollution is a major factor that can disrupt the relative biological equilibrium in ecosystems. Its harmful effects on water, air, soil, and the overall functioning of ecological processes can lead to the decline of species, imbalances in food chains, and the degradation of ecosystems. Therefore, it is crucial to take measures to reduce pollution and protect the environment for the maintenance of relative biological equilibrium.