Science Form Quiz: Exercise With Answers

Water is represented by the chemical formula H2O, which indicates that each molecule of water consists of two hydrogen atoms bonded to one oxygen atom. This formula explains why water is a vital solvent and participates in various chemical reactions, including supporting life processes. Water is essential for all known forms of life and is a major component of many organisms. It also helps regulate temperature and maintain homeostasis within living organisms.

The heart is the primary organ responsible for pumping blood throughout the body. It is a muscular organ that contracts rhythmically to circulate blood, delivering oxygen and nutrients to tissues and removing waste products. The heart is central to the circulatory system. Without the heart's continuous pumping action, the body's cells would not receive the necessary nutrients and oxygen to function properly. The heart works in conjunction with blood vessels to ensure proper circulation throughout the body.

The boiling point of water is 100°C at sea level. At this temperature, water changes from liquid to gas. This is a physical change, and the temperature remains constant until all the water has converted to steam. Atmospheric pressure can affect this boiling point. The higher the atmospheric pressure, the higher the boiling point of water. Conversely, at higher altitudes where atmospheric pressure is lower, water boils at a lower temperature.

 The alveolus is a  tiny air sac in the lungs where the exchange of gases, specifically oxygen and carbon dioxide, occurs. Oxygen from the inhaled air diffuses into the bloodstream through the thin walls of the alveoli, while carbon dioxide, a waste product, diffuses out of the bloodstream into the alveoli to be exhaled. This exchange of gases is essential for respiration and supplying oxygen to the body's cells. The other options, rib, bronchiole, and bronchus, are not directly involved in the exchange of gases.

The symbol 'O' represents the element oxygen on the periodic table. Oxygen is a non-metal and is essential for respiration in most living organisms. It is colorless, odorless, and tasteless, making up about 21% of the Earth's atmosphere by volume. Oxygen is also a key component in the process of combustion, supporting the burning of fuels. Additionally, oxygen plays a crucial role in the formation of ozone in the Earth's stratosphere, providing protection from harmful ultraviolet radiation.

 The respiratory system is responsible for the intake of oxygen and carbon dioxide in the body. The nasal cavity is part of the respiratory system as it filters, warms, and moistens the air we breathe. The alveolus is a tiny air sac in the lungs where oxygen and carbon dioxide are exchanged with the bloodstream. The bronchus is a tube that carries air into the lungs. The aorta and atrium are not directly related to the respiratory system. The aorta is the main artery that carries oxygenated blood from the heart to the rest of the body, and the atrium is one of the chambers of the heart.

The O blood type is not known as the universal recipient. The O blood type is known as the universal donor because it lacks both A and B antigens on the red blood cells, making it compatible with all other blood types. This means that individuals with O blood type can donate blood to recipients with any other blood type without fear of rejection. However, individuals with O blood type can only receive blood from other O donors.

Plants use carbon dioxide during photosynthesis to produce glucose and oxygen. This process takes place in the chloroplasts where sunlight provides the energy needed to convert carbon dioxide and water into glucose, a form of sugar that plants use for energy and growth. Oxygen is released as a byproduct of this process, which is essential for the survival of most living organisms on Earth. Without photosynthesis, plants would not be able to produce their own food and the oxygen levels in the atmosphere would decrease significantly.

The trachea does not branch into bronchioles. After the trachea, it branches into two tubes called bronchi, which further divide into smaller tubes called bronchioles. Bronchioles are responsible for carrying air to the alveoli, where gas exchange occurs. These small airways are essential for the process of respiration in the lungs. The bronchioles are lined with smooth muscle that helps regulate airflow and diameter. Additionally, they lack cartilage support, allowing for greater flexibility and movement during breathing.

 Phloem tissue is responsible for the movement of food throughout a plant. It contains sieve tubes, which are specialized cells that transport sugars, amino acids, and other organic compounds produced during photosynthesis. These nutrients are transported from the leaves, where they are produced, to other parts of the plant, such as the roots, stems, and fruits, where they are needed for growth, energy, and storage.

When light passes through a prism, it undergoes refraction, which means the light bends due to a change in speed as it enters a different medium. A prism has the ability to split white light into a spectrum of colors (visible light spectrum) because different colors of light bend at slightly different angles. The separation of colors happens because each color has a different wavelength, causing each to refract differently. This phenomenon is known as dispersion.

 Nicotine is a highly addictive substance found in tobacco products. It stimulates the release of dopamine in the brain, creating pleasurable feelings and reinforcing the desire to use it again. The addictive nature of nicotine can lead to dependence and cravings, making it difficult for individuals to quit smoking or using other nicotine products.

The penis is an external reproductive organ in males that is responsible for delivering sperm into the female reproductive system. Sperm is actually produced in the testes, which are located inside the scrotum, a sac-like structure below the penis. The penis is composed of spongy tissue that becomes engorged with blood during sexual arousal, leading to an erection. The urethra, a tube that carries both urine and semen, runs through the penis.

The correct answer is binary fission and regeneration. Binary fission is a type of asexual reproduction where a single organism divides into two identical daughter cells. Regeneration is another type of asexual reproduction where an organism can regrow lost or damaged body parts to form a complete individual. Both binary fission and regeneration are common methods of asexual reproduction in various organisms.

Resin is not an excretory product of rubber trees. Resin is a sticky substance that is produced by certain plants as a protective coating for wounds or as a defense against insects or pathogens. It is not directly related to rubber trees, which produce latex as their excretory product.

The term "budding" refers to a form of asexual reproduction where a smaller organism grows out of the body of a larger organism. Yeast is a type of fungus that reproduces through budding, where a small bud grows out of the parent cell and eventually detaches to become a new individual. Amoebas, moulds, and planaria reproduce through other methods such as binary fission or fragmentation, making yeast the only organism in the given list that exhibits budding.

The vena cava is a large vein that carries deoxygenated blood from all parts of the body back to the right atrium of the heart. There are two branches of the vena cava: the superior vena cava, which receives blood from the upper body, and the inferior vena cava, which receives blood from the lower body. Together, they ensure that deoxygenated blood is returned to the heart to be pumped to the lungs for oxygenation.

The urinary bladder is not a part of the kidneys. The kidneys are responsible for filtering waste products from the blood and producing urine, while the urinary bladder is a separate organ that stores urine before it is eliminated from the body. The other options, medulla, pelvis, and cortex, are all parts of the kidneys. The medulla is the innermost region, the pelvis is the central cavity that collects urine before it is transported to the bladder, and the cortex is the outer layer of the kidneys where filtration takes place.

During inhalation, the ribcage moves up and outward to expand the chest cavity, allowing the lungs to fill with air. This movement is facilitated by the contraction of the diaphragm and intercostal muscles, creating negative pressure within the thoracic cavity and drawing air into the lungs. Exhalation, on the other hand, involves the relaxation of these muscles and the elastic recoil of the ribcage, which compresses the lungs and forces air out. This process is crucial for removing carbon dioxide from the body and maintaining proper gas exchange in the respiratory system.

The human excretory system consists of several organs and structures that work together to remove waste products from the body. The kidneys are the main organs responsible for filtering waste from the blood and producing urine. The renal artery and renal vein are blood vessels that supply and drain blood to and from the kidneys. The urethra is a tube that carries urine from the bladder to the outside of the body. The urinary bladder is a muscular sac that stores urine until it is ready to be expelled. The ureters are tubes that transport urine from the kidneys to the bladder. While the skin is primarily associated with functions such as temperature regulation and protection, it also plays a role in excretion through the sweat glands. Sweat contains water, salts, and small amounts of waste products like urea, providing another route for waste removal.