Daily Quiz: UPSC Prelims Marathon – February 15, 2018

Blood transports substances like digested food from the small intestine to the other parts of the body. It carries oxygen from the lungs to the cells of the body. It also transports waste for removal from the body.

Blood is a liquid, which has cells of various kinds suspended in it. The fluid part of the blood is called plasma. One type of cells are the red blood cells (RBC) which contain a red pigment called haemoglobin.

They are two types of blood vessels namely arteries and veins.

Veins are the blood vessels that carry carbon dioxide-rich blood [impure blood] from all parts of the body back to the heart. Pulmonary vein is an exception as it carries oxygen-rich blood [pure blood] from lungs to heart. The veins have thin walls.

Arteries are the blood vessels that carry oxygen-rich blood from heart to all parts of the body. Pulmonary artery is an exception as it carries carbon dioxide-rich blood from heart to lungs. The arteries have thick walls as the pressure acting on then is high.

Both the statements are correct. A flexible-fuel vehicle (FFV) or dual-fuel vehicle (colloquially called a flex-fuel vehicle) is an alternative fuel vehicle with an internal combustion engine designed to run on more than one fuel, usually gasoline blended with either ethanol or methanol fuel, and both fuels are stored in the same common tank.

Flex-fuel vehicles are distinguished from bi-fuel vehicles, where two fuels are stored in separate tanks and the engine runs on one fuel at a time, for example, compressed natural gas (CNG), liquefied petroleum gas (LPG), or hydrogen.

Statement 1 is correct. When the surrounding atmosphere heats up, plants will often release excess water into the air from their leaves through the process of transpiration.  By releasing evaporated water, plants cool themselves and the surrounding environment.

Statement 2 is incorrect. When we place a plant under the fan the speed of air flow is very high. Transpiration will take place in presence of high air flow through the stomata. Rate of transpiration increases during windy condition. Increase in the rate of transpiration increases the water absorption also because when transpiration occurs, it will create a transpiration pull and more water absorption will take place.

Statement 1 is incorrect. Carbon dioxide is heavier and denser than oxygen. Oxygen is required for combustion. Being heavier than oxygen, it covers the fire like a blanket and cuts off the contact between fuel and oxygen, thereby extinguishing the fire.

Statement 2 is correct. Carbon dioxide quickly expands enormously in volume and cools down. This brings down the temperature of the fuel and consequently controls the fire.

Statement 3 is correct. Carbon di oxide being a bad conductor of electricity, it can be safely used to extinguish fire from electrical equipment.

Statement 1 is incorrect. Arsenic is released in the environment due to Acidification of water bodies. Acidification is the ongoing decrease in the pH of the water, caused by the uptake of carbon dioxide (CO2) from the atmosphere.

Statement 2 is correct. The Earth’s crust is an abundant natural source of arsenic. Volcanic action is the most important natural source. The next most important source is arsenic-containing vapor that is generated from solid or liquid forms of arsenic salts at low temperatures.

Statement 3 is correct. Industrial processes such as mining, smelting and coal-fired power plants all contribute to the presence of arsenic in air, water and soil. Environmental contamination also occurs because it is used in agricultural pesticides and in chemicals for timber preservation.

Teeth and Bones can have fluorosis affect.

Fluoride can have both a positive and a negative impact on tooth enamel. Generally, the higher the concentrations of fluoride in drinking water the smaller the likelihood to develop dental caries. However, the prevalence and severity of dental fluorosis within the population increases with the concentration of fluoride in drinking water.

Bones can be negatively affected by fluoride. Cases of skeletal fluorosis are associated with high levels of fluoride in drinking water or in ambient air at work or at home, for instance in areas of China in which coal rich in fluoride is used indoors on open fires for heating and cooking. Although fluoride is the cause of skeletal fluorosis in these cases, many other factors, including nutritional factors, can play a significant role in the severity of the health condition.

Light waves are many times faster than sound waves. Hence, when there is lightning, the light waves reach us faster than the sound waves. For this reason, we see lightning much before we hear its thunder.