Vidaara.orgClass 10 · Mathematics
CodeVID-M10-WS
Heredity — Practice Worksheet
Name: ____________________
Roll No.: __________
Date: ____________
General Instructions
- All questions are compulsory.
- Choose the correct option (A, B, C or D) for each question.
- The answer key is at the end — try the paper first!
Section A — Multiple Choice (1 mark each)
15 × 1 = 15 marks
1.
The transmission of characters from parents to offspring is called:
- A.Variation
- B.Heredity
- C.Nutrition
- D.Excretion
2.
Differences in characters among individuals of a species are called:
- A.Variations
- B.Genes
- C.Reflexes
- D.Tropisms
3.
The units of inheritance that control traits are:
- A.Genes
- B.Neurons
- C.Villi
- D.Alveoli
4.
Mendel carried out his famous experiments on:
- A.Garden pea plants
- B.Mango trees
- C.Mice
- D.Bacteria
5.
In Mendel's cross of pure tall and short peas, the F₁ plants were all:
- A.Short
- B.Tall
- C.Medium
- D.Half tall, half short
6.
The F₂ ratio of dominant to recessive traits in Mendel's monohybrid cross was:
- A.1 : 1
- B.3 : 1
- C.2 : 2
- D.9 : 7
7.
A trait that is expressed (shows up) when present is called:
- A.Recessive
- B.Dominant
- C.Acquired
- D.Hidden
8.
An organism with two identical alleles (e.g. TT) is:
- A.Heterozygous
- B.Homozygous
- C.Recessive only
- D.Variant
9.
The sex chromosomes in a human female are:
- A.XY
- B.XX
- C.YY
- D.XO
10.
The sex of a human child is determined by the:
- A.Mother's egg
- B.Father's sperm
- C.Diet of the mother
- D.Age of parents
11.
All human eggs carry which sex chromosome?
- A.X
- B.Y
- C.Both X and Y
- D.Neither
12.
The gradual change in a species over many generations is called:
- A.Heredity
- B.Evolution
- C.Reflex
- D.Pollination
13.
A wrestler's strong muscles are an example of a/an:
- A.Inherited trait
- B.Acquired trait
- C.Recessive gene
- D.Sex chromosome
14.
Forelimbs of humans, birds and whales have a similar structure but different uses. They are:
- A.Analogous organs
- B.Homologous organs
- C.Fossils
- D.Genes
15.
The theory of evolution by natural selection was proposed by:
- A.Gregor Mendel
- B.Charles Darwin
- C.Isaac Newton
- D.Robert Hooke
Section B — Challenge / Olympiad (2 marks each)
6 × 2 = 12 marks
16.
Two heterozygous tall pea plants (Tt) are crossed. The chance that an offspring is short (tt) is:
- A.1 in 4
- B.1 in 2
- C.3 in 4
- D.0
17.
A couple has three daughters. The chance that their fourth child is a son is:
- A.About 1 in 2 (50%)
- B.Certain to be a son
- C.Impossible
- D.1 in 4
18.
Why does a recessive trait reappear in the F₂ generation though it was absent in F₁?
- A.Each plant carries two factors; in F2 some get two recessive factors
- B.New genes are created in F2
- C.The dominant gene is destroyed
- D.It is an acquired trait
19.
The bones of a human arm and a bat's wing have a similar basic plan. This is evidence that they:
- A.Share a common ancestor
- B.Have no relationship
- C.Are acquired traits
- D.Cannot evolve
20.
Fossils are useful in the study of evolution because they:
- A.Show what organisms of the past looked like and how life changed
- B.Are living organisms
- C.Are acquired traits
- D.Determine sex
21.
Natural selection leads to evolution because, over generations:
- A.Organisms with helpful inherited variations survive and reproduce more
- B.Acquired traits are passed on
- C.All variations disappear
- D.Genes never change
Answer Key
Section A — Multiple Choice (1 mark each)
- (B) Heredity
- (A) Variations
- (A) Genes
- (A) Garden pea plants
- (B) Tall
- (B) 3 : 1
- (B) Dominant
- (B) Homozygous
- (B) XX
- (B) Father's sperm
- (A) X
- (B) Evolution
- (B) Acquired trait
- (B) Homologous organs
- (B) Charles Darwin
Section B — Challenge / Olympiad (2 marks each)
- (A) 1 in 4
- (A) About 1 in 2 (50%)
- (A) Each plant carries two factors; in F2 some get two recessive factors
- (A) Share a common ancestor
- (A) Show what organisms of the past looked like and how life changed
- (A) Organisms with helpful inherited variations survive and reproduce more
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