Q1:-Give examples of two variations found in humans.
Ans: – 1. Human height
2. Free earlobe and attached earlobe

Q2:- Write the names of the components of DNA?
Ans: – Components of DNA are nucleotides. Each nucleotide has further three components-
1. Deoxyribose sugar
2. A nitrogenous base
3. A phosphate group
Q3:-Give two examples where environmental factors govern sex-determination?
Ans: – a) In turtle, high incubation temperature results in the development of female progeny.
b) In lizard high incubation temperature results in male progeny.
Q4:- What is genetic engineering? Give the full form of GMO.
Ans: – It is the technique of altering the genetic make up of an organism by inserting gene (or segment of DNA) from other organism into its DNA.
Q5:- How are the areas of study – evolution and classification interlinked?
Ans:-Classification of organisms is based on relative similarities and differences among organisms. Resemblances in organisms are because they have arisen from a common ancestor and differences are due to adaptations to different types of environment. As the organisms can be graded in order of increasing complexity, it indicates the concept evolution.
Q6:-Why are small numbers of surviving tigers a cause worry from the point of view from genetics?
Ans: – With decreasing number of tigers, their genetic pool is also vanishing which is essential to maintain the ecological and food chain balance.
Q7: – Will geological isolation be a major factor in the speciation of an organism that reproduces asexually? Why or Why not?
Ans: -During asexual reproduction organisms undergo a little variation over generations .The variation in the genetic pool are not enough to raise a new species .Thus, any change resulting from geographical isolation may not be passed to the next generation.
Q7: -A man with blood group ‘A’ marries a women blood group ‘O’ and their daughter has blood group ‘O’. Is this information enough to tell you which of the traits –blood group ‘A’ or ‘O’ is dominant? Why or Why not?
Ans: – Blood group ‘A’ is dominant while ‘O’ is recessive character. If a man with blood group ‘A’ marries a woman with blood group ‘O’ and their daughter has blood group ‘O’ , then the man has one copy of ‘A’ and one copy of ‘O’ blood group.

Q8: – Differentiate between autosomes and sex chromosomes.
Ans: – 1. The pair of chromosomes that are responsible for development of body characters are called autosomes .In human body, there 22 pairs of autosomes.
2.The pair of chromosomes which are responsible for determining the sex of the individual called sex chromosomes .
Q9: -Why Mendel selected garden pea plant for his experiment.
Ans: – Mendel selected garden pea plant for his experiment because-
1. Pure varieties of pea were available.
2. Pea plants showed a number of easily detectable contrasting characters.
3. The flower structure of pea is such that it allows controlled breeding.
4. Pea flower normally remains closed and undergoes self pollination.
Q10:-How is the equal genetic contribution of male and female parents ensured in the progeny?
Ans:-The gametes responsible for the formation of progeny develop by the process of meiosis. During meiosis only one set of chromosomes (50% of Gene) is transferred to the gamete. When male and female gametes fuse, one set of chromosome from each parent cell come together and complete the genetic pool.So, progeny receives 50% genetic contribution through each gamete(male and female).http://sciencehelpline.blogspot.com