General Science

Lymph is a clear fluid that lacks red blood cells (erythrocytes), which is the key difference from blood. It contains white blood cells (lymphocytes) but no red blood cells or platelets. Lymph does contain plasma-like fluid (lymphatic fluid), so option A is incorrect. The absence of red blood corpuscles gives lymph its characteristic clear/pale yellow color rather than the red color of blood.

Asbestos minerals are primarily silicates of magnesium (e.g., chrysotile is Mg3Si2O5(OH)4). While magnesium is correct, calcium is not a major component of asbestos - this appears to be an error in the question or answer key. Among the given options, C is the closest to being correct since it includes magnesium, but scientifically, magnesium silicate alone would be more accurate.

Ethyl alcohol (ethanol) is invariably produced during fermentation processes. This is a defining characteristic of fermentation - the conversion of sugars into ethanol and carbon dioxide by yeast or bacteria. Methyl alcohol and acetic acid are not typical products of standard alcoholic fermentation, and yeast is the agent that produces alcohol, not the product itself.

Correct Answer: is an evolutionary theory

Sodium carbonate (washing soda) does not cause hardness because sodium salts of higher fatty acids are water-soluble, unlike calcium and magnesium salts which form insoluble precipitates (soap scum). The other options are incorrect: sodium carbonate is soluble in water, color is unrelated to water hardness, and being crystalline has no connection to water softening.

Velocity is a vector quantity defined as the rate of change of position with respect to time in a definite direction. Unlike speed (which is scalar), velocity specifies both magnitude and direction. Option B only describes speed, while option D correctly includes both the rate aspect (speed) and the directional requirement that makes it velocity.

As an object falls under gravity, its height decreases which reduces its gravitational potential energy (PE = mgh). This lost potential energy is converted into kinetic energy (KE = 1/2 mv^2) as the object gains speed. The total mechanical energy remains constant (ignoring air resistance), so the gain in KE exactly equals the loss in PE.

Dialysis works on the principle of osmosis, where solvent molecules move across a semipermeable membrane from a region of lower solute concentration to higher solute concentration. The dialysis membrane allows small molecules and waste products to pass through while retaining larger proteins and blood cells in the patient's blood.

Work done against friction is negative because the frictional force always acts opposite to the direction of displacement. When we calculate work as W = F·d·cos(theta), the angle between friction force and displacement is 180°, giving cos(180°) = -1. This negative work represents energy dissipated as heat.

Correct Answer: Bits

At high altitudes, atmospheric pressure drops significantly while blood pressure remains relatively constant. This pressure differential causes the blood pressure in capillaries to exceed the external air pressure, making delicate nasal capillaries more prone to rupture and bleeding. Option B is incorrect because air pressure decreases, not increases, at higher altitudes. Option C is misleading - blood pressure doesn't inherently increase, but the pressure differential becomes more significant.

A retrorocket is a rocket engine fired in the opposite direction of motion to provide braking thrust. They are essential for slowing down spacecraft during reentry, orbital maneuvers, or landing operations. Option A describes a standard accelerator rocket, while retrorockets specifically decelerate. Options C and D incorrectly describe retrorockets as primary vehicles rather than auxiliary propulsion systems.

In a vacuum, air resistance is absent. According to Galileo's principle, all objects accelerate at the same rate due to gravity regardless of their mass. A feather, wooden ball, and steel ball will all fall with identical acceleration and hit the ground simultaneously.

A short circuit occurs when current flows directly between two points at different electrical potentials, bypassing the normal load or resistance in the circuit. This creates a low-resistance path that can cause excessive current flow, potentially damaging equipment or causing fires.

Yellow light has the longest wavelength in the visible spectrum and scatters less in fog and rain compared to other colors. This makes yellow lights penetrate better through adverse weather conditions, providing improved visibility for drivers.

Correct Answer: decrease

Metal is an excellent thermal conductor due to free electrons that transfer heat rapidly. Porcelain, glass, and clay are thermal insulators with much lower thermal conductivity, so they retain heat longer. Tea cools fastest in the metal cup.

Persistence of vision refers to the phenomenon where the human eye retains an image for about 1/16th of a second after it disappears. Cinema exploits this by showing sequential frames at 24 frames per second, creating the illusion of continuous motion.

Correct Answer: Graphite

Sound waves are mechanical waves that transport energy through a medium. They do not transport mass (particles only oscillate) and do not transport 'sound' itself - sound is the energy wave. The wave carries energy from source to receiver.

Television signals travel in straight lines and cannot follow Earth's curved surface. Beyond the horizon (the line of sight limited by Earth's curvature), signals cannot be received without repeaters or satellites. This is why TV reception was limited to a specific distance.

Car headlights use parabolic concave mirrors because they reflect light rays from the bulb placed at the focus into a parallel beam. This creates a strong directional light that illuminates the road ahead effectively. Plane or convex mirrors would scatter light.

Oncology is the branch of medicine that specializes in the study, diagnosis, and treatment of tumors (cancer). The term comes from 'onco' meaning tumor or mass. Orthopedics studies bones, virology studies viruses, and ornithology studies birds.