Free Forest Ecology MCQs with Answers

• A. None of these
• B. Ecological cycles
• C. Chemical cycles
• D. Biochemical cycles

Explanation: Biochemical cycles describe the circulation of elements such as carbon, nitrogen and phosphorus between organisms and the physical…

• A. Nitrogen
• B. Oxygen
• C. Carbon
• D. None of these

Explanation: Nitrogen is a structural component of amino acids in proteins and nitrogenous bases in nucleic acids.

• A. 58
• B. 78
• C. 68
• D. None of these

Explanation: Nitrogen makes up approximately 78% of Earth’s atmosphere by volume, mainly as N₂ gas.

• A. Food web
• B. None of these
• C. Food cycle
• D. Food chain

Explanation: A food chain is a linear sequence through which energy passes from plants to successive consumers by eating and being eaten.

• A. Fossil fuels
• B. Natural gas
• C. Oil
• D. Coal

Explanation: Fossil fuels, including coal, petroleum and natural gas, are non-renewable resources formed over geological periods.

• A. Heart diseases
• B. Kidney trouble
• C. Gastric diseases
• D. None of these

Explanation: Smoke containing soot and fine particles irritates the eyes and can contribute to systemic diseases, including kidney problems, through…

• A. No time
• B. In ten minutes
• C. In five minutes
• D. In fifteen minutes

Explanation: At about 1% concentration, carbon monoxide combines with haemoglobin so rapidly that oxygen transport is critically blocked and death may…

• A. Sulphuric acid, sulphurous acid nitric acid and, nitrous acid
• B. Nitric acid alone
• C. Nitrous acid and sulphurous acid
• D. Sulphuric acid alone

Explanation: Acid rain forms when sulphur and nitrogen oxides react with atmospheric moisture, producing sulphuric, sulphurous, nitric and nitrous…

• A. Urbanization
• B. Industrialization
• C. Mechanization
• D. Civilization

Explanation: Industrialization releases smoke, gases and particulate matter from factories and fuel combustion, making it a major direct cause of air…

• A. 50% to 80%
• B. 40% to 60%
• C. 70 to 90%
• D. 80% to 90%

Explanation: Water commonly makes up roughly 70 to 90 percent of the mass of living organisms, although the exact proportion varies among species and…

• A. Irrigation
• B. Industry
• C. In making dams
• D. Irrigation and industry

Explanation: Most freshwater withdrawals are used for agriculture, especially irrigation, with industry accounting for much of the remainder; domestic…

• A. Erosion and trampling by animals
• B. Poor agricultural practices and excessive water
• C. Over-grazing and extensive ploughing
• D. Erosion, poor agricultural practices and over grazing

Explanation: Land is abused when human activities or their consequences degrade it, including erosion, unsuitable farming practices and overgrazing.

• A. Construction of canals
• B. Construction of bridges
• C. Rapid urbanization
• D. Erosion

Explanation: Rapid urbanization converts agricultural or natural land to built-up surfaces and often causes unplanned land-use change.

• A. Thickness
• B. Porosity
• C. Fertility
• D. Nitrates

Explanation: Soil pollution can disrupt aggregation and pore spaces, but its most important productive consequence is loss of fertility through damage…

• A. Sulphate fertilizers
• B. Insecticides
• C. Phosphate fertilizers
• D. Nitrate fertilizers

Explanation: Excess nitrate fertilizer adds large amounts of reactive nitrogen to ecosystems, disturbing natural nitrogen cycling and causing leaching…

• A. Nuclear power plants
• B. Hdroelectric power
• C. Fossil fuels
• D. Solar energy

Explanation: Fossil fuels such as oil, gas and coal have historically supplied the great majority of Pakistan's energy, far more than nuclear or solar…

• A. Radioactive element
• B. Radioactive cell
• C. Radioactive substance
• D. Radioactive atom

Explanation: In a nuclear fission reaction, the nucleus of a radioactive atom such as uranium-235 is split, releasing energy and more neutrons.

• A. Uranium-235
• B. Uranium-234
• C. Uranium-236
• D. Uranium-237

Explanation: Uranium-235 is fissile and can sustain a chain reaction with slow neutrons, so it is the principal conventional nuclear fuel in reactors…

• A. Cancer of skin and bone
• B. Cancer of skin and bone marrow
• C. Cancer of heart and brain
• D. Cancer of kidneys

Explanation: High-energy ionising radiation can damage DNA and produce cancers, especially in exposed tissues such as the skin and the blood-forming…

• A. Flowing water
• B. River water
• C. Dam water
• D. Falling water

Explanation: Hydroelectricity uses the potential energy of water at a height, which is converted into kinetic energy as the water falls through…