Answer:
2. The lime water turns milky in colour
3. To act as filters
4. To enable easy penetration of the root of planted crops.
See detailed explanation below
Explanation:
2. Our exhaled air principally contains carbon dioxide gas (CO2), which reacts with like water to produce a milky solution. The lime water is a solution of Calcium hydroxide (CaOH2), which chemically reacts with the C02 content of our exhaled air to form a compound called Calcium carbonate (CaCO3). Calcium carbonate is a whitish compound that appears chalky/milky.
3. Our nostrils contain a cavity called nasal cavity, which is lined with mucus (a viscous substance). The mucus helps to keep the nasal cavity wet. The hair in the nostrils also help prevent large particles in inhaled air from entering into the nasal cavity. The hair and mucus works together to filter out shirts and germs like bacteria etc from entering into the lungs.
4. Farmers loosen the soil which they plant their crops by mixing the layers of the soil. Loosening the soil encourages or promotes a deep and easier penetration of the plant roots. It also helps the soil to be properly drained and aerated i.e. penetration of water and air into the soil respectively.
