CSS General Science and Ability MCQs - 2025

Perinatal transmission occurs when a pathogen is transmitted from a mother to her baby. This transmission happens during the perinatal period, which encompasses late pregnancy and the early postpartum period. Pathogens involved can include bacteria, viruses, or parasites. Understanding this transmission route is critical for preventing and managing infections in newborns. Various interventions, such as screening and preventative medications, can reduce the risk of perinatal transmission.

• Bryophytes (e.g., mosses) require water for sperm motility but live on land.

• Tracheophyta (B) includes vascular plants (ferns, trees) less dependent on water.

• Wind energy results from temperature differences (due to solar heating), creating air movement.

• Solar (B) is the primary source, but wind is the direct manifestation of uneven heating.

Space Waves are used for line-of-sight (LOS) communication. This is because LOS communication requires a direct path between the transmitter and receiver, and space waves are able to travel in a straight line, making them suitable for this type of communication. Space waves are also used for satellite communication due to their propagation characteristics. This makes them ideal for applications where a clear, unobstructed path is available between the communication devices.

• Shallow earthquakes (<30 km) displace large volumes of water, generating tsunamis.

• Deeper earthquakes (>50 km) rarely cause significant tsunamis due to reduced energy transfer.

• Gelatin prevents ice crystal formation, improving texture.

• Sugar (A) sweetens; milk (B) is the base.

• Total internal reflection traps light in the core due to the refractive index difference.

• Refraction (B) bends light; diffraction (C) spreads it.

The amount of data transmitted per unit time is called bandwidth. Bandwidth refers to the maximum rate at which data can be transferred over a network or internet connection in a given amount of time. 

• Whole grains (wheat, rice) are rich in complex carbohydrates.

• Nuts (A) provide fats; plant oil (B) is pure fat.

• Jugging involves slow-cooking meat in a sealed jug (traditionally with blood/wine).

• Curing (C) uses salt/smoke, not stewing.

The fastest enzyme is Carbonic anhydrase. It can catalyze the hydration of CO2 to form bicarbonate at a rate of 600,000 molecules per second. This reaction is significantly faster than the reaction that would occur without the enzyme, by a factor of 10

• Silicosis (or cytosilicosis) is caused by inhaling silica dust in cement factories.

• Leukemia (A) and Bone marrow (C) are unrelated.

Guava is used for jam (crushed fruit) and jelly (strained juice with pectin).

• John McCarthy coined the term "AI" in 1956 and organized the Dartmouth Conference.

• Turing (C) proposed the Turing Test but didn’t invent AI.

• 🌟 Red Giants:
  These are old stars that have exhausted the hydrogen in their cores and expanded enormously. They are cooler on the surface (hence red) but very luminous due to their large size.

• 🔵 Blue Dwarfs:
  These are theoretical future stars — small, hot stars that would form as red dwarfs exhaust their hydrogen fuel and become hotter and bluer. None exist yet because the universe isn’t old enough for any red dwarf to have evolved that far.

Python is a very common language for AI development due to its versatility and extensive libraries. Java is also frequently used for AI implementation, and the best choice depends on project needs. Python's popularity stems from its readability and a large ecosystem of AI-focused libraries like TensorFlow and PyTorch, which make it easier to build and deploy AI models. Java's robustness and performance make it suitable for large-scale AI applications. Both languages offer excellent tools for various AI applications.

Operating systems initialize their total memory from the BIOS (Basic Input/Output System). The BIOS is a firmware that initializes hardware components during the boot process, including the system's RAM. It performs tests, sets up the initial hardware configuration, and makes the memory available to the operating system. The OS then takes over memory management after the BIOS completes its initial setup.

Global winds moving towards the western direction are known as trade winds. These winds play a crucial role in global weather patterns and are a significant factor in maritime navigation, historically. Trade winds consistently blow from east to west near the equator, contributing to the movement of ocean currents. They're also vital for the climate of the regions they impact. Understanding trade winds is fundamental to grasping broader atmospheric circulation.

Adding vitamins to milk is called fortification. This process involves adding essential micronutrients like vitamins A and D to enhance the nutritional value of milk. Fortification is a common practice to improve public health by addressing potential vitamin deficiencies. It's important to note that fortification is not limited to milk and is used in various food products.

• Insects (Class Insecta) comprise ~80% of all animal species.

• Fish (A) and mammals (C) have far fewer species.