Class 10 Science Chapter 9 MCQ Online Test for 2020-2021
| Class: 10 | Science |
| Chapter: 9 | Heredity and Evolution |
| Contents: | MCQ Online Tests with Answers and Explanation |
Class 10 Science Chapter 9 MCQ with Answers for 2020-21
Class 10 Science Chapter 9 MCQ Online Test with solutions and answers. All the questions are taken from NCERT intext part as well as exercises section. Answers and explanation are also taken from NCERT Books for Class 10 Science only.
Q1
The number of pair (s) of sex chromosomes in the zygote of humans is
[A]. One
[B]. Two
[C]. Three
[D]. Four
Answer: Option A
Explanation:The number of sex chromosomes in the zygote of humans is one pair. It is not always a perfect pair. In females, it is perfect with two X-chromosomes. However, in males, there is one X-chromosome and one Y-chromosome.
Q2
In peas, a pure tall plant (TT) is crossed with a short plant (tt). The ratio of pure tall plants to short plants in F2 is
[A]. 1 : 3
[B]. 3 : 1
[C]. 1 : 1
[D]. 2 : 1
Answer: Option C
Explanation:When pure bred tall plant with phenotype (TT) crossed with short plant with phenotype (tt), the possible progeny in F2 generation: TT (1), tt (1) and Tt (2). Thus the ratio of pure tall (TT) to pure short (tt) is 1:1.
Q3
The two versions of a trait (character) which are brought in by the male and female gametes are situated on
[A]. Copies of the same chromosome
[B]. Two different chromosomes
[C]. Sex chromosomes
[D]. Any chromosome
Answer: Option A
Explanation:The two versions of a trait a sweet situated on copies of same chromosome. Each parent contributes one copy of the gene for a particular character. In the gamete however, only one copy is present due to reduction division. At the time of fusion, the diploid condition is maintained. Sex chromosomes carry genes for sexual characters.
Q4
According to the evolutionary theory, formation of a new species is generally due to
[A]. Sudden creation by nature
[B]. Accumulation of variations over several generations
[C]. Clones formed during asexual reproduction
[D]. Movement of individuals from one habitat to another
Answer: Option B
Explanation:Accumulation of variation over several generation forms new species. Genetic drift accumulates different changes in sub-populations of a species. Also, natural selection may also operate differently in the different geographic location. Eventually different groups of new species will be formed.
Q5
Select the correct statement
[A]. Tendril of a pea plant and phylloclade of Opuntia are homologous
[B]. Tendril of a pea plant and phylloclade of Opuntia are analogous
[C]. Wings of birds and limbs of lizards are analogous
[D]. Wings of birds and wings of bat are homologous
Answer: Option D
Explanation:Wings of birds and wings of bat are “Homologous”. Since they have some basic design however their origin is different.
Q6
Select the incorrect statement
[A]. Frequency of certain genes in a population change over several generations resulting in evolution
[B]. Reduction in weight of the organism due to starvation is genetically controlled
[C]. Low weight parents can have heavy weight progeny
[D]. Traits which are not inherited over generations do not cause evolution
Answer: Option B
Explanation:The weight reduction due to starvation will not change the DNA of the germ cells, because low weight is not a trait that is genetically controlled or inherited. Thus, low weight parents may have heavy weight progeny.
Traits which are not inherited, i.e. the acquired traits are simply changes in non-reproductive tissues, so, cannot be passed on to DNA of germ cell.
Evolution results from change in frequency of genes in a population over several generations.
Q7
Zygote which has an X-chromosome inherited from the father will develop into a
[A]. Boy
[B]. Girl
[C]. X- chromosome does not determine the sex of a child
[D]. Either boy or girl
Answer: Option B
Explanation:A zygote that has an X-chromosome inherited from father will develop into a girl.
All children weather boys or girls inherited an X-chromosomes from their mother. Thus, sex is determined by what they inherited from their father. A child who inherits X-chromosome from her father will be a girl, and one who inherits a Y-chromosome from him will be a boy.
Q8
If a round, green seeded pea plant (RR yy) is crossed with wrinkled, yellow seeded pea plant, (rr YY) the seeds produced in F1 generation are
[A]. Round and yellow
[B]. Round and green
[C]. Wrinkled and green
[D]. Wrinkled and yellow
Answer: Option A
Explanation:The cross between RRyy and rrYY seeds will produce RrYy (round and yellow) seeds in F1 generation, because round and yellow are dominant traits.
Q9
Which of the following may be used to obtain an F2 generation?
[A]. Allowing flowers on a parent plant to be self-pollinated
[B]. Allowing flowers on an F1 plant to be self-pollinated
[C]. Cross-pollinating an F1 plant with a parent plant
[D]. Cross-pollinating two parent plants
Answer: Option A
Explanation: F2 generation can be obtained by allowing flowers on the plants of F1 generation to be self-pollinated.
Q10
In order to ensure that he had pure-breeding plants for his experiments, Mendel:
[A]. Cross-fertilised each variety with each other
[B]. Let each variety self fertilise for several generations
[C]. Removed the female parts of the plants
[D]. Removed the male parts of the plants.
Answer: Option B
Explanation: Mendel ensured that he used pure breeding plants for his experiments by letting each variety self-pollinate for several generations
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Which type of traits can be inherited?
Those Variations, which arise during the process of reproduction, can be inherited.
What is meant by heredity?
Transfer of traits from parents to offspring is called heredity.
How do we determine the age of fossil?
There are two components to determine the age. One is, if we dig into the earth and start finding fossils, it is reasonable to suppose that the fossils we find closer to the surface are more recent than the fossils we find in deeper layers. The second way of dating fossils is by detecting the ratios of different isotopes of the same element in the fossil material.
What are fossils?
When a living being dies and the dead body gets caught in hot mud, for example, it will not decompose quickly, and the mud will eventually harden and retain the impression of the body parts of the living being. All such preserved traces of living organisms are called fossils.
