This set of Class 12 Biology Chapter 13 Multiple Choice Questions & Answers (MCQs) focuses on “Organisms and Populations – Major Abiotic Factors – 1”.
1. Which of the following is known as an edaphic abiotic factor?
Explanation: The edaphic abiotic factor is soil. Edaphic itself means related to soil. Soil is an important abiotic factor affecting the growth of plants. Soil provides support, minerals, and water to plants.
2. Which of the following is known as a topographic abiotic factor?
a) Earth’s surface
Explanation: The topographic abiotic factor is the Earth’s surface. It tells about the physical features of a surface or region. It contains geographic positions and elevations for both natural and man-made features.
3. What is the temperature at hydrothermal sea vents?
Explanation: The hydrothermal sea vents are present at sea-floor. It includes geysers or hot springs present on the ocean floor which contains geothermally heated water. It has a temperature above 100°C which may rise up to 400°C.
4. Which animal is not found in the forests of Kerala?
d) Snow leopard
Explanation: Snow leopards are not found in the forests of Kerala. They are native to mountain ranges of central and north Asia. They require low temperatures for survival while Kerala has high temperatures and no snowfall.
5. Which one of the following is an abiotic factor?
Explanation: Among the following humidity is an abiotic factor. Humidity is invisible to vapors in the atmosphere. It directly affects the vegetation by affecting the rate of transpiration in plants. The rate of transpiration increases with a decrease in humidity.
6. What are plants growing at high temperatures alternatively called?
Explanation: The plants growing at high temperatures are termed as megatherms. These plants usually grow near the equator in tropical rainforests. They need abundant moisture along with high temperatures.
7. What are plants growing in high-low temperature called?
Explanation: Mesotherms are plants that survive at a high temperature of summer along with a low temperature of winter. They are found deciduous forests of tropical and subtropical regions.
8. What are plants growing at low temperatures called?
Explanation: Plants growing at low temperatures are called microtherms. They are found in temperate regions with high altitudes. Mostly consists of coniferous plants.
9. What are plants growing at very low temperatures called?
Explanation: Hekistotherms are the plants growing at very low temperatures. They are found in tropic regions (Arctic and Alpine). Alpine plants grow maximally at low temperatures.
10. What are warm-blooded animals called?
Explanation: The warm-blooded animals are called homeotherms. They have the ability to maintain their body temperature at a constant level despite the change in temperature of the surrounding environment. Examples are mammals, birds.
11. What are cold-blooded animals called?
Explanation: Poikilotherms are cold-blooded animals. They cannot regulate their body temperature and take on the temperature of their surrounding environment. An example is reptiles.
12. Which is a universal solvent?
Explanation: Water is a universal solvent. It can dissolve almost any solute that is solid, liquid or gas. It is polar in nature and can form various types of bonds and interactions with other molecules.
13. What are plants growing in an aquatic environment called?
Explanation: Plants growing in or on the water are called hydrophytes. They survive in water for such a long time with the help of osmosis. They have a large number of stomata on the upper surface which helps in more loss of water and helps in survival.
14. Which one of the following is a problem for aquatic animals?
d) Endo osmosis
Explanation: Endo-osmosis is a problem for aquatic animals. It leads to an increase in body fluid concentration which may lead to cell lysis. Also, exo-osmosis may also harm these animals as this leads to water loss from the body leading to shrinkage and dehydration.
15. Organisms that can tolerate a wide range of salinities are called?
Explanation: Organisms that can tolerate a wide range of salinities are called euryhaline. These organisms can live in fresh, brackish or salty water. An example is a salmon.
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