The question asks why whales come to the surface of the water. To answer this, we need to understand the basic biological needs of whales, specifically their respiratory system. Whales are mammals, and unlike fish, they do not have gills to extract oxygen from water.
C) To exhale and inhale air. Whales are mammals, and like all mammals, they breathe air using lungs. They cannot extract oxygen from water like fish. Therefore, they must regularly surface to expel carbon dioxide and take in fresh oxygen. This is a fundamental physiological requirement for their survival.
The question asks to identify the plant part that contains stomata, which are essential for gas exchange. We need to recall the primary functions of different plant parts and where stomata are predominantly located.
Correct Option: B) Leaf — Leaves are the primary photosynthetic organs and possess numerous stomata on their epidermal surface to facilitate the exchange of gases (carbon dioxide and oxygen) and regulate transpiration.
The question asks about the specific role of lime water in a breathing experiment. This refers to a common laboratory demonstration used to show the presence of carbon dioxide in exhaled air. Understanding the chemical properties of lime water is key to answering this question.
B) To detect CO₂ — Lime water (calcium hydroxide solution) reacts with carbon dioxide to form insoluble calcium carbonate, which appears as a milky precipitate. This property is used to test for the presence of carbon dioxide, especially in experiments demonstrating the composition of exhaled air.
The question asks about the product of anaerobic respiration in yeast. Anaerobic respiration is a metabolic process that occurs in the absence of oxygen. Different organisms produce different end products through this process.
Specifically, the chemical equation is:
\[ \text{C}_6\text{H}_{12}\text{O}_6 \rightarrow 2\text{C}_2\text{H}_5\text{OH} + 2\text{CO}_2 + \text{Energy} \]B) Alcohol — Anaerobic respiration in yeast is also known as alcoholic fermentation, where glucose is broken down into ethanol (alcohol) and carbon dioxide in the absence of oxygen.
UPSC - 2019
The question asks about the applications of RNA interference (RNAi) technology. RNAi is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA molecules. We need to evaluate each given statement to determine its validity as an application of RNAi.
Based on the analysis, statements 1, 2, and 4 are correct.
A) 1, 2 and 4. This option includes all the correct statements regarding the applications of RNA interference technology.
The question asks why we breathe faster after running. This relates to the physiological changes that occur in the body during and after strenuous physical activity. We need to consider the body's immediate needs when muscles are working hard.
C) To supply more oxygen to cells. Running increases muscle activity, which requires more energy. This energy is generated through aerobic respiration, a process that consumes oxygen. Therefore, breathing faster helps deliver more oxygen to the cells to meet this increased demand and also helps remove the excess carbon dioxide produced.