Class 10 Science Chapter 6 MCQ

The various organs in sequence of mouth, oesophagus, stomach, small intestine and large intestine and anus. The nutrition in human beings take place through the digestive system, that consists of alimentary canal and associated glands.

It is incorrect as; autotrophs can convert carbon dioxide and water into carbohydrates only in the presence of sunlight. The autotrophs contain the green pigment called chlorophyll which is capable of trapping sun energy. This trapped energy is utilised by them to make food by combining inorganic materials like CO2 and H2O by the process of photosynthesis. The food that is not used immediately, is stored in the form of starch. These autotrophs constitute the first trophic level in food chains.

The first step is the break-down of glucose, a six-carbon molecule, into a three-carbon molecule called pyruvate. This process takes place in the cytoplasm.

The correct path of urine is Kidney → Ureters → Urinary bladder → Urethra. The urine formed in each kidney eventually enters a long tube, the ureter, which connects the kidneys with the urinary bladder. Urine is stored in the urinary bladder until the pressure of the expanded bladder leads to the urge, to pass it out through the Urethra.

Non-living things which are not alive cannot move by themselves. For example, a stone is a non-living thing which cannot move by itself from one place to another or show any other type of movement. We will have to move it by applying force from outside.

Cells generally does not share the transaction of the particles or molecules.

The small intestine is the site of the complete digestion of carbohydrates, proteins and fats. It receives Bile juice, the secretions of the liver and also pancreatic juice from pancreas for this purpose.

The solution turned blue-black in colour just because of starch.

Nitrogen is an essential element used in the synthesis of proteins and other compounds. This is taken up in the form of inorganic nitrates or nitrites. Sometimes it is taken up as organic compounds i.e., urea, which have been prepared by bacteria from atmospheric nitrogen.

Green plants are autotrophic and synthesize their own food by the process of photosynthesis. The process of photosynthesis can be represented as: 6CO2 + 6 H2O + Sunlight + Chlorophyll → C6H12O6 + 6O2 (releases)

Alveoli of lungs. The walls of the alveoli contain an extensive network of blood-vessels. When we breathe in, we lift our ribs and flatten our diaphragm, and the chest cavity becomes larger as a result. Because of this, air is sucked into the lungs and fills the expanded alveoli. The blood brings carbon dioxide from the rest of the body for release into the alveoli, and the oxygen in the alveolar air is taken up by blood in the alveolar blood vessels to be transported to all the cells in the body.

Oxygen-rich blood from the lungs comes to the thin-walled upper chamber of the heart on the left, the left atrium. The left atrium relaxes when it is collecting this blood. It then contracts, while the next chamber, the left ventricle, relaxes, so that the blood is transferred to it. When the muscular left ventricle contracts in its turn, the blood is pumped out to the body. De-oxygenated blood comes from the body to the upper chamber on the right, the right atrium, as it relaxes. As the right atrium contracts, the corresponding lower chamber, the right ventricle, dilates. This transfers blood to the right ventricle, which in turn pumps it to the lungs for oxygenation. Since ventricles have to pump blood into various organs, they have thicker muscular walls than the atria do. Valves ensure that blood does not flow backwards when the atria or ventricles contract.

Valves allow the flow of blood in one direction only.

Here, all the statements are correct. Hence your answer will be option [D].

Here, all the statements are correct. Hence your answer will be option [D].

Hippocampus, Exocoetus, Anabas. Because the rate of energy required for the body activities is very low.

The following events occur in photosynthesis (i) Absorption of light energy by chlorophyll. (ii) Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen. (iii) Reduction of carbon dioxide to carbohydrates.

Living things can move by themselves. The plants are fixed in the soil at a place so they cannot move like animals from place to place but the plants can only move parts of their body such as leaves, flowers, roots etc.

Non-living things which are not alive cannot move by themselves. For example, a stone is a non-living thing which cannot move by itself from one place to another or show any other type of movement. We will have to move it by applying force from outside.

Left ventricle pumps oxygenated blood to different body parts while right ventricle pumps deoxygenated blood to lungs. Whereas right atrium receives deoxygenated blood from different parts of the body while left ventricle pumps oxygenated blood to different parts of the body. Hence, Deoxygenated blood flows through the right side of the heart. Oxygenated blood flows through the left side of the heart.

The opening and closing of the pore is a function of the guard cells. The guard cells swell when water flows into them, causing the stomatal pore to open. Similarly the pore closes if the guard cells shrink.

When we breathe in, we lift our ribs and flatten our diaphragm, the chest cavity becomes larger. Alveoli is balloon like structure which provides a surface where the exchange of gases occurs the walls of alveoli consist of network of blood-vessels. The air is sucked into the lungs to fill the expanded alveoli. The blood brings carbon dioxide from the rest of the body for release into the alveoli. And the oxygen in the alveolar air is taken up by blood in the alveolar blood vessels to be transported to all the cells in the body. In human beings, the respiratory pigment is haemoglobin which has a very high affinity for oxygen. This pigment is present in the red blood corpuscles. The human lungs have millions of air sacs called alveoli whose surface area is many that of the body. These are involved in exchange of gases.

Carbon dioxide gas turns limewater milky. When air is blown from mouth into test, the lime water turns milky because the air we breathe out has more CO2.

Generally, the normal blood pressure values are: Systolic pressure: 120 mm Hg Diastolic pressure: 80 mm Hg This is usually written as 120 by 80.

The small intestine in human beings is the site of complete digestion of food. It is also the main region for absorption of digested food. However, digestion begins in the mouth cavity, food is further digested in the stomach to form a semi-solid paste. The undigested food from small intestine passes into large intestine that absorb most of the water.