Q14 of 56 Page 1

"The father is responsible for the sex of a child, not the mother." Justify this statement.

(i) "The father is responsible for the sex of a child, not the mother." This statement is completely justified and can be proved as follows:

A male has XY chromosomes and a female has XX chromosomes.


1. If a sperm carrying X chromosome from male gets combined with the X chromosome from female, then the combination will be XX and child will be a baby girl.


2. If a sperm carrying Y chromosome from male gets combined with the X chromosome from female, then the combination will be XY, and the child will be a baby boy.


More from this chapter

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8

(a) Which two criteria did Mendeleev use to classify the elements in his periodic table?

(b) Which element of period '3' of the modern periodic table


(i) is the most reactive non-metal?


(ii) is the most reactive metal?


(iii) forms ion with -2 charge?


(iv) forms ion with +2 charge?

 10

Define the term, dispersion of white light. State the color which bends (i) the least,

(ii) the most, while passing through a glass prism. Draw the dispersion of light through prism.

 17

(a) How are the following related?

(i) Number of valence electrons of different elements in the same group.


(ii) Number of shells of elements in the same period.


(b) How do the following change?


(i) Number of shells of elements as we go down a group.


(ii) Number of valence electrons of elements on moving from left to right in a period.


(iii)Atomic radius in moving from left to right along a period.


(iv) Atomic size down a group.

 18

A 2.4 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 18 cm. The distance of the object from the lens is 12 cm. Find the position, size and nature of the image formed, using the lens formula.