Human beings have 4 distinct types of teeth, each serving a specific mechanical purpose: incisors (cutting), canines (tearing), premolars (crushing), and molars (grinding).
42. Artificial lakes were made in earlier time in order to save ………………. Water.
(A) Ground water
(B) Rain water
(C) Fresh water
(D) Drinking water
Answer:
(B) Rain water
Explanation:
Historically, especially in arid regions like Rajasthan, rulers constructed vast artificial lakes (like Gadsisar Lake) specifically to harvest, collect, and save rain water for dry periods.
43. Salt and sugar remove ………………….. from the food.
(A) germs
(B) bacteria
(C) water
(D) taste
Answer:
(C) water
Explanation:
Salt and sugar act as natural preservatives by creating a hypertonic environment, which draws water (moisture) out of the food via osmosis, inhibiting the growth of decay-causing bacteria.
44. The process of loosening the soil is called:
(A) levelling
(B) Ploughing
(C) weeding
(D) harvesting
Answer:
(B) Ploughing
Explanation:
Ploughing (or tilling) is the agricultural process of physically turning over, breaking up, and loosening the top layer of soil to prepare it for planting seeds.
45. Which nutrient protect us against disease?
(A) Vitamins and minerals
(B) Fats and Carbohydrate
(C) Protein
(D) All of these
Answer:
(D) All of these
Explanation:
While vitamins and minerals are specifically classified as “protective foods,” a fully functioning immune system requires energy from carbohydrates and structural repair from proteins.
