CBSE Questions for Class 10 Biology Heredity And Evolution Quiz 4 - MCQExams.com

The traits that Mendel studied are listed below:

• Form of seed  smooth (R) or wrinkled (r)
  
• Colour of seed yellow  (Y) or green (y)
  
• Colour of flower  purple (P) or white (p)
  
• Form of pods  inflated (I) or constricted (i)
  
• Colour of pods  green (G) or yellow (g)
  
• Position of flowers  axial (A) or terminal (a)
  
• Height of plant  tall (T) or dwarf (t)

Mendel did not know about genes or discover genes, but he did speculate that there were two factors for each basic trait and that one factor was inherited from each parent.

We now know that Mendel's inheritance factors are 'genes', more specifically 'alleles', different variants of the same gene.

 $$\textbf{Correct option: }$$ C

$$\textbf{ Solution: }$$

$$\textbf{ Option (C): }$$

$$\bullet$$The water freezes to form ice which becomes lighter than any solid materials. 

$$\bullet$$This characteristic of ice allows the water to expand when cooled and becomes less dense. 

$$\bullet$$This allows aquatic life to survive below the sheet of ice in the antarctic region. 

Hence, the correct answer is option (C).

• Sex is determined by two chromosomes, X and Y. A female is XX, a male is XY. 
• Since women completely lack the Y chromosome, they always contribute an X chromosome to the baby. The sex of the baby is determined by, whether the sperm that fertilizes the egg is carrying chromosome Y or another X.
• Thus, the correct answer is A.
  

Mendel picked pea plants for his experiment. The reasons for the selection of pea plants for the genetic experiments are: 
1) Easy to grow in the garden.
2) Pea plants can be self-fertilized (easy to obtain pure breed plants).
3) The generation time of pea plants is less. 
4) Pea plants have easily identifiable traits.
Thus, the correct answer is option D.

• The evolutionary process by which new biological species arise is called speciation. 
• Speciation can be driven by evolution, which is a process that results in the accumulation of many small genetic changes called mutations in a population over a long period of time.
  
• It is an irreversible process. 

• Fossils provide direct evidence of evolution. 
• Fossils are body remains of dead plants and animals or their impressions preserved in layers of the Earth and rocks. 
• The fossil position in the layer of earth relates to the time of extinction of organisms, If the fossil of an organism is found in the deeper layers of earth, then it is predicted that extinction of organisms has occurred thousands of years ago.

• The evolution has lead several morphological and genetic changes in the organism which leads to better adaptation. 
• Chimpanzees make tools and use them to acquire foods and for social displays. 
• They have sophisticated hunting strategies requiring cooperation, influence and rank, they are status conscious, manipulative and capable of deception. 
• They can also learn to use symbols and understand aspects of human language and are capable of spontaneous planning for a future state or event. 
• So, they are most intelligent apes compared to gibbon, orangutan and gorilla.
• Thus, the correct answer is option D.

Solution

Correct answer is option B.

Explanation for correct option:

• Fertilization is the process of fusion of nuclei of two haploid reproductive cells, sperm (n) and egg or oocyte (n) to produce a diploid zygote (2n).
• Sperm and egg carries the genes from father and mother respectively. Since unitedly they form a zygote, it has genes from both the parents equally. 

• Presence of observable traits with contrasting characters
• Produces many offspring in one cross
• Short life cycle
• Ease in manipulating pollination (cross pollination)