PPSC Past Paper 2023

Explanation:

The correct answer is (C) East because when Venus serves as the Morning Star, it rises low on the horizon shortly before dawn, serving as a directional beacon for East.

The Morning Star: Because Venus orbits closer to the Sun than Earth, it is always seen in the same general region of the sky as the Sun. During its 263-day morning phase, it appears in the eastern sky before sunrise, outshining all other celestial bodies except the Moon.
Celestial Navigation: For ancient travelers, sailors, and nomadic tribes who lacked magnetic compasses, tracking the pre-dawn appearance of this brilliantly reflective planet served as a vital natural indicator to identify the eastern cardinal direction.
Incorrect Options:
(A) North is incorrect because tracking the North direction at night relies on tracking stars like Polaris (the North Star) or utilizing constellations like the Big Dipper rather than inner planets.
(B) South is incorrect because planets do not sit stationary at the Southern celestial pole, which requires tracking specific configurations like the Southern Cross constellation in the Southern Hemisphere.
(D) West is incorrect because although Venus does indicate the West when it acts as the Evening Star right after sunset, general knowledge curriculum questions traditionally focus on its role as the eastern Morning Star.

Explanation: • Venice is called the City of Canals and is built on 118 islands

• Rome is known as the Eternal City

• Paris is called the City of Light

• Istanbul lies on two continents (Asia & Europe)

• Tokyo is the most populous metropolitan city

• Mecca is the holiest city of Islam

• Karachi is the largest city of Pakistan by population

• Islamabad is the planned capital of Pakistan.

Explanation: Satellites revolve around planets. For example, the Moon is a satellite of Earth.

Explanation: Entomology – study of insects

Botany – study of plants

Zoology – study of animals

Microbiology – study of microorganisms

Ichthyology – study of fishes

Ornithology – study of birds

Herpetology – study of reptiles and amphibians

Explanation: Nylon is a synthetic polymer that does not decompose easily through natural biological processes, making it non-biodegradable.

Explanation:

The correct answer is (B) Cornea because it is the specific transparent outer tissue of the eye that is harvested and transplanted to restore vision.

Keratoplasty Procedure: When a person donates their eyes after death, a surgeon utilizes the clear, dome-shaped front surface known as the cornea to replace a recipient's damaged or diseased cornea in a surgical procedure called a corneal transplant.
Structural Limitations: Unlike the cornea, complex neural frameworks located in the back of the eye cannot be repaired or reattached to a new host through modern transplantation methods.
Incorrect Options:
(A) Retina is incorrect because it is a highly complex layer of nerve tissue at the back of the eye that cannot be transplanted due to the impossibility of reconnecting millions of delicate nerve pathways.
(C) Iris is incorrect because this colored muscular ring controls the amount of light entering the eye and is not the structural tissue replaced during sight-restoring transplant procedures.
(D) Optic nerve is incorrect because it functions as the main data cable sending signals from the eye to the brain, and modern medicine cannot transplant or splice central nervous system pathways.

Explanation: The cell theory was proposed by Matthias Schleiden and Theodor Schwann in the 19th century.