CASE STUDY–1: Bacterial Population
A population of bacteria was exposed to high temperature. Most bacteria died, but a few survived and reproduced. After some time, the population consisted mainly of heat-resistant bacteria.
CS-1.1
The surviving bacteria lived because they had
A. No variations
B. Useful variations
C. Perfect DNA
D. Larger size
Answer: B
CS-1.2
The heat-resistant trait was present because of
A. Growth
B. Nutrition
C. DNA copying errors
D. Migration
Answer: C
CS-1.3
This situation best explains the process of
A. Reproduction
B. Heredity
C. Natural selection
D. Digestion
Answer: C
CS-1.4
If temperature returns to normal, the heat-resistant bacteria will
A. Die immediately
B. Lose the trait
C. Continue to survive
D. Stop reproduction
Answer: C
CASE STUDY–2: Human Traits
In a family, children show similarities with parents but are not exactly identical. Some have attached earlobes, while others have free earlobes.
CS-2.1
The similarities are due to
A. Same environment
B. Same food habits
C. Inheritance of traits
D. Growth rate
Answer: C
CS-2.2
Difference in earlobes shows
A. Disease
B. Variation
C. Injury
D. Ageing
Answer: B
CS-2.3
The presence of two types of earlobes indicates
A. Acquired traits
B. Learned behaviour
C. Genetic variation
D. Environmental pressure
Answer: C
CS-2.4
Such variations are important because they
A. Reduce population
B. Stop inheritance
C. Help species survival
D. Eliminate growth
Answer: C
CASE STUDY–3: Sexual vs Asexual Reproduction
A farmer grows sugarcane using stem cuttings, while another grows plants using seeds.
CS-3.1
Sugarcane plants show little variation because they reproduce by
A. Sexual reproduction
B. Spore formation
C. Vegetative propagation
D. Pollination
Answer: C
CS-3.2
Plants grown from seeds show more variation because
A. DNA is destroyed
B. Two parents contribute DNA
C. Growth is faster
D. Environment is fixed
Answer: B
CS-3.3
Which method helps faster evolution?
A. Vegetative propagation
B. Asexual reproduction
C. Sexual reproduction
D. Fragmentation
Answer: C
CS-3.4
Low variation in sugarcane can be risky because
A. Growth slows
B. Survival during environmental change reduces
C. Reproduction stops
D. DNA disappears
Answer: B