Heredity and Evolution

What you'll learn

Explore how traits pass from parents to offspring through genes, Mendel's dominant and recessive rules with a monohybrid cross, human sex determination, and the basics of evolution.

This chapter has

Heredity and Evolution — solved practice questions

8 Class 10 Science questions with step-by-step solutions. Attempt each, then reveal the answer.

1. Q1easy

   The transmission of characters from parents to offspring is called:

   • Aevolution
   • Bheredity
   • Cvariation
   • Dmutation
   Show answer & solution

   Correct answer: (B) heredity

   Heredity is the biological inheritance of traits from parents to their offspring.

2. Q2easy

   'Father of Genetics' is:

   • ADarwin
   • BMendel
   • CMorgan
   • DLamarck
   Show answer & solution

   Correct answer: (B) Mendel

   Gregor Johann Mendel is called the Father of Genetics for his work with pea plants in the 1860s.

3. Q3medium

   Mendel's Law of Segregation states that:

   • Aalleles separate during gamete formation
   • Btraits blend in offspring
   • Cacquired characters are inherited
   • Dgenes are on chromosomes
   Show answer & solution

   Correct answer: (A) alleles separate during gamete formation

   Alleles of a gene segregate (separate) during gamete formation so each gamete carries only one allele.

4. Q4easy

   A 'dominant' trait is one that:

   • Aexpresses in one copy
   • Bexpresses only in two copies
   • Cis always harmful
   • Dappears in every generation
   Show answer & solution

   Correct answer: (A) expresses in one copy

   A dominant trait expresses itself even when only one copy (allele) is present.

5. Q5medium

   A 'recessive' trait is expressed:

   • Aalways
   • Bonly in homozygous recessive
   • Cwhen dominant is absent
   • Dnever
   Show answer & solution

   Correct answer: (B) only in homozygous recessive

   A recessive allele is expressed only when both copies are recessive (homozygous recessive).

6. Q6medium

   Crossing TT (tall) × tt (dwarf) pea plants. All F₁ plants are:

   • Atall (Tt)
   • Bdwarf (tt)
   • Chalf tall and half dwarf
   • Dnone are tall
   Show answer & solution

   Correct answer: (A) tall (Tt)

   TT × tt → all Tt (tall), since T is dominant over t.

7. Q7medium

   The ratio of tall : dwarf in F₂ (from Tt × Tt) is:

   • A1:1
   • B3:1
   • C1:2:1
   • D1:3
   Show answer & solution

   Correct answer: (B) 3:1

   Tt × Tt → TT : Tt : tt = 1:2:1. Tall (TT+Tt) : dwarf (tt) = 3:1.

8. Q8hard

   Acquired characteristics are NOT inherited. This idea refutes:

   • ADarwinism
   • BLamarck's theory
   • CMendelism
   • Dmutation theory
   Show answer & solution

   Correct answer: (B) Lamarck's theory

   Lamarck's theory (inheritance of acquired characters) is rejected by modern genetics. Acquired changes in soma do not affect DNA in germline.

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