General Science

1. 'Blue baby syndrome' is due to the presence of which of the following in the blood?

A) Haemoglobin
B) Methemoglobin
C) Lead
D) Nitrate

Answer: Option B) Methemoglobin

Explanation:

The presence of methemoglobin in the blood causes a disease called 'blue baby syndrome'. Hemoglobin changes into methemoglobin and reduces the oxygen supply in the body, which causes cyanosis (i.e. blue discoloration of the skin) in the body. It affects infants more than adults. When the oxygen level drops too much, the affected person goes into a coma and if there is no improvement, death is also possible.

2. Site of gaseous exchange in lungs is

A) Tracheoles
B) Bronchioles
C) Pulmonary vein
D) Alveoli

Answer: Option D) Alveoli

Explanation:

The site of gaseous exchange in the lungs is the alveoli or alveoli. Alveoli are called the structural and functional unit of the respiratory system. When a person breathes through the nose, the air goes into an organ called trachea in the throat, which is also called the windpipe. Further, the trachea gets divided into many parts, which are called bronchial tubes. Inside the bronchioles, there is an air sac, which is called alveoli.

3. Which of the following vitamins is essential for normal vision?

A) Folic acid
B) Riboflavin
C) Niacin
D) Retinol

Answer: Option D) Retinol

Explanation:

Retinol (vitamin A) is essential for normal vision. Its deficiency can lead to problems like scaling of cornea and skin cells, night blindness, stunted growth, keratomasia, etc. Milk, butter, egg, liver, fish oil, spinach, etc. are the main sources of vitamin A.