CBSE Questions for Class 8 Biology Reaching The Age Of Adolescence Quiz 1 - MCQExams.com

• There are 23 pairs of chromosomes present in a human cell except for gametes, which makes it a total of 46 chromosomes. 
• Out of these, 22 pairs are autosomes and the remaining one is the pair of sex chromosomes.

The adrenal glands secrete hormones which maintain the correct salt balance in the blood.

The correct option is A.  

• Human females carry two copies of X chromosomes as sex chromosomes and hence, transmit them to both male and female offspring. 
• But human male has one X and one Y chromosome as sex chromosomes. If the father transmits "X" to the child, the sex of the child will be female (XX) and a girl child will be born. While, if the child gets "Y" from the father, it will be a male offspring (XY). 
• Hence, the type of sex chromosome of the father determines the sex of child/offspring/progeny in humans.

• The female gamete or egg has only X chromosome as the sex chromosome.
• The male gametes or sperms can have either X or Y chromosome as the sex chromosome.
• Sex in humans is determined by the type of sperm that fuses with the female egg. 
• When the sperm with the X chromosome fuses with the egg, then the child will be female (XX).
  
• When the sperm with the Y chromosome fuses with the egg, then the child will be male (XY).
  
• Hence, we can say that the key factor for sex determination in humans is the Y chromosome. 

• At puberty, the voice box or the larynx begins to grow. 
• Boys develop larger voice boxes. The growing voice box in boys can be seen as a protruding part of the throat called Adam’s apple. 
• In girls, the larynx is hardly visible from the outside because of its small size.
• Generally, girls have a high-pitched voice, whereas boys have a deep voice.
• In adolescent boys, sometimes, the muscles of the growing voice box go out of control and the voice becomes hoarse. 
• This state may remain for a few days or weeks after which the voice becomes normal.

• The human male has 22 pairs of autosomes and one pair of sex chromosomes- XY.
• The human female has 22 pairs of autosomes and one pair of sex chromosomes - XX.
• So, the correct answer is option C.

• Menarche is the first occurrence of menstruation and marks the beginning of the reproductive period.
• Menopause is the end of menstruation and marks the end of the reproductive period in women.

Correct option: Correct option: This hormone regulates the metabolism of an organism and is also involved in the process of  metamorphosis showing the developmental changes in the life span of an organism.

Hence, the correct answer is option (D)

• The reproductive cycle in females is called the menstrual cycle.
• The first menstrual flow begins at puberty and is termed menarche. 
  
• In human females, menstruation is repeated at an average interval of about 28/29 days. 
• So, the correct answer is option C.