RBSE Solutions Class 9 Science Chapter 5 Concept of Life

Objective Type Questions

Question 1. In-Universe, life is possible on which planet after earth?
(A) Mercury
(B) Jupiter
(C) Venus
(D) Mars
Answer: (D) Mars
In simple words: Besides Earth, Mars is the most likely planet in our solar system where life could exist or has existed. Scientists continue to explore Mars for signs of past or present life.

🎯 Exam Tip: Remember Mars is often called the "Red Planet" and is the fourth planet from the Sun, known for its thin atmosphere and polar ice caps.

Question 2. Which character among the following is not found in non-living things:
(A) Reproduction
(B) Development
(C) Growth
(D) All of the options
Answer: (D) All of the options
In simple words: Non-living things do not grow, develop, or reproduce. These are special abilities only found in living organisms.

🎯 Exam Tip: When distinguishing between living and non-living things, remember key characteristics like reproduction, growth, development, metabolism, and response to stimuli.

Question 3. Due to Oparin's hypothesis, the origin of life is divided into how many stages?
(A) 5
(B) 6
(C) 7
(D) 8
Answer: (C) 7
In simple words: Oparin's idea about how life started on Earth is explained in seven main steps. Each step builds on the last, from simple chemicals to the first living things.

🎯 Exam Tip: Understanding the sequence of stages in Oparin's hypothesis is crucial for questions on the origin of life.

Question 4. Who gave the theory of Biogenesis?
(A) Oparin
(B) Francescoredi
(C) Van Helmont
(D) Leabig
Answer: (B) Francescoredi
In simple words: The idea that life only comes from other life (biogenesis) was first shown by Francesco Redi through his experiments. This helped to challenge the old idea that life could appear from non-living matter.

🎯 Exam Tip: Associate Francesco Redi with the theory of biogenesis and his famous experiment using meat in jars to disprove spontaneous generation.

Concept of Life Very Short Answer Type Questions

Question 6. Which scientist rejected the theory of Spontaneous Generation?
Answer: Louis Pasteur rejected the theory of Spontaneous Generation. His famous swan-neck flask experiment showed that microbes do not spontaneously arise from non-living matter but come from pre-existing microbes in the air.
In simple words: Louis Pasteur proved that living things do not just pop up from non-living stuff, which helped stop the old idea of spontaneous generation.

🎯 Exam Tip: When asked about spontaneous generation, always remember Louis Pasteur and his conclusive experiment.

Question 7. Name the two planets which show similarity with earth?
Answer: The two planets showing similarity with Earth are:
1. Kepler-452b
2. Kepler-186f
These exoplanets are located in the habitable zone of their respective stars, meaning they could potentially have liquid water and support life.
In simple words: Two planets, Kepler-452b and Kepler-186f, are thought to be like Earth because they are in the right spot around their own stars to have water.

🎯 Exam Tip: In this context, "planets" refers to exoplanets, which are planets outside our solar system that share Earth-like characteristics.

Question 8. Who advocated the cosmozoic theory?
Answer: The cosmozoic theory was advocated by Richter. This theory suggests that life exists throughout the Universe and is distributed by meteoroids, asteroids, and planetoids.
In simple words: Richter was the one who said that life might have come to Earth from space.

🎯 Exam Tip: Remember Richter as the proponent of the cosmozoic theory, which posits life's origin from outside Earth.

Concept of Life Short Answer Type Questions

Question 9. Explain the difference between living and non-living with an example?
Answer: Living things require food, air, and water; they breathe, grow, and move on their own. For example, a dog breathes, eats, grows, and moves. Non-living things, in contrast, do not show any of these characteristics. For instance, a rock does not need food, cannot grow, and does not move by itself.
In simple words: Living things need food and grow, like a plant. Non-living things do not do these things, like a stone.

🎯 Exam Tip: Focus on fundamental biological processes like respiration, growth, and movement to highlight the key differences between living and non-living entities.

Question 10. Explain the experiment of Miller with a diagram.
Answer: Stanley Miller performed an experiment to support Oparin's theory, demonstrating how simple organic molecules could have formed on early Earth. Miller set up an apparatus with methane (\( \text{CH}_4 \)), ammonia (\( \text{NH}_3 \)), hydrogen (\( \text{H}_2 \)), and water (\( \text{H}_2\text{O} \)). He passed a 60,000-volt electric discharge through this mixture for a week. One side of the apparatus had boiled water, while the other circulated the condensed water mixture. After a week, a red-colored liquid formed. Upon analysis, this liquid contained several amino acids, glycerine, alanine, and other organic compounds. This showed that complex organic substances could evolve from simple gases under early Earth conditions.
In simple words: Miller mixed gases like those on early Earth and added electricity. He found that simple building blocks of life, like amino acids, were formed. This showed how life might have started from non-living things.

🎯 Exam Tip: To describe Miller's experiment well, mention the gases used (methane, ammonia, hydrogen, water vapor), the energy source (electric discharge), and the key result (formation of amino acids and other organic compounds).

Question 11. Describe the theory of Biogenesis?
Answer: Biogenesis is the theory that life originates only from pre-existing life. Francesco Redi challenged the spontaneous generation hypothesis through his experiment. He showed that abiogenesis (life from non-life) does not occur. Redi placed cooked fish meat in three jars: one uncovered, one covered with parchment, and one covered with a fine muslin cloth. After a few days, maggots appeared only in the uncovered jar. Flies were seen laying eggs on the muslin cloth of the third jar, but maggots appeared in the meat, showing that they arose from eggs laid by parent flies, not spontaneously. Louis Pasteur also confirmed that even the simplest microorganisms develop from existing microorganisms, not from spontaneous generation.
In simple words: Biogenesis is the idea that all life comes from other life. Francesco Redi proved this with an experiment using meat and flies. He showed that living things do not just appear from non-living things.

🎯 Exam Tip: When explaining biogenesis, clearly state that life comes from life and refer to Redi's experiment as key evidence against spontaneous generation.

Concept of Life Long Answer Type Questions

Question 12. Name the various theories related to the origin of life? Explain any one of them?
Answer: The origin of life has been explained through various theories, which include:
(a) Theory of special creation
(b) Theory of spontaneous generation (Abiogenesis)
(c) Cosmozoic Theory (Theory of cataclysm or catastrophism)
(d) Catastrophe Theory (Mechanist theory)
(e) Theory of eternity
(f) Theory of biogenesis
(g) Modern theory (The chemical origin of life)

A hypothesis of spontaneous generation of life on Earth:
According to this theory, life originated from lifeless or non-living substances. It suggested that various types of animals and plants could suddenly or spontaneously appear without any clear cause. This theory was widely accepted because of a lack of scientific explanations at the time. However, it was later rejected when it was proven that organisms do not appear from inanimate, non-living objects. This theory highlights how early scientific thought sometimes relied on observations without deeper understanding.
In simple words: Many ideas exist about how life started. One old idea, spontaneous generation, said life could just appear from non-living things, like bugs from mud. This idea was later proven wrong because living things always come from other living things.

🎯 Exam Tip: List as many theories of life's origin as possible. When asked to explain one, choose one you understand well and clearly outline its main idea and its fate (accepted or rejected).

Question 1. Explain the differences between the living and non-living?
Answer: Living and non-living things have many clear differences in how they function and what they are made of. Living things can grow, move, breathe, and reproduce, all thanks to complex processes happening inside them. Non-living things, however, lack these abilities and remain inert unless acted upon by an external force. Here are the key differences:

🎯 Exam Tip: When comparing living and non-living things, always remember key features like growth, reproduction, respiration, and movement. Providing a clear table helps to organize your answer and score full marks.