PPSC Everyday Science Past Paper 2021 Solved MCQs with Answers
Solved Everyday Science MCQs from the PPSC 2021 past paper, each with the correct answer and a clear explanation. Ideal practice for PPSC, FPSC, NTS, CSS and PMS. All questions are extracted from the actual 2021 paper and verified before publication.
What is the diameter of the Small Magellanic Cloud (SMC)?
The Small Magellanic Cloud is about 7,000 light years across.
In which constellations is the Large Magellanic Cloud located?
The Large Magellanic Cloud lies across the constellations Dorado and Mensa.
In which constellations is the Small Magellanic Cloud located?
The Small Magellanic Cloud lies in Tucana and Hydrus.
What is the mass of the Large Magellanic Cloud?
The Large Magellanic Cloud has a mass of about 10 billion suns.
What is the mass of the Small Magellanic Cloud?
The Small Magellanic Cloud has a mass of about 6.5 billion suns.
Which galaxy is described as a spiral galaxy?
Andromeda, M31, is a spiral galaxy.
Which galaxy is described as elliptical?
Messier 87 is a giant elliptical galaxy.
The Andromeda Galaxy has a:
Andromeda has a crowded double nucleus, two concentrations of stars around its central black hole.
The Milky Way's age is closest to:
The Milky Way, at about 13.6 billion years, is nearly as old as the universe itself.
Which is the closest large galaxy to the Milky Way?
Andromeda is the closest large galaxy to us. The Magellanic Clouds are nearer but far smaller.
M87 is the home of approximately how many globular star clusters?
M87 holds about 15,000 globular star clusters, many times the number around the Milky Way.
According to the higher end of current estimates, how many stars does the Milky Way contain?
Estimates of the Milky Way's stars run from about 100 billion to 400 billion.
Total number of bones in the adult human body:
An adult human has 206 bones. A newborn has about 270, which fuse as the child grows.
Estimated number of cells in the human body:
The human body is estimated to hold about 37.2 trillion cells.
Largest cell in the human body:
The ovum is the largest human cell, and the only one visible to the naked eye.
Longest cell in the human body:
The neuron is the longest cell, some running from the spinal cord to the toe.
Smallest cell in the human body:
The sperm is the smallest human cell.
Average adult blood volume:
An adult carries about 5 to 6 litres of blood.
RBCs produced per second:
The body makes about 2 to 3 million red blood cells every second.
Lifespan of a red blood cell:
A red blood cell lives about 120 days before the spleen removes it.
Protein in RBCs that carries oxygen:
Haemoglobin carries oxygen in the red cells.
Main metal in haemoglobin:
Iron sits at the centre of the haem group, and is what binds the oxygen.
Cells that fight infection:
Leukocytes, the white blood cells, fight infection.
Cells responsible for blood clotting:
Platelets, or thrombocytes, are responsible for clotting.
Number of blood-clotting factors:
There are 13 recognised blood clotting factors.
Universal blood donor group:
Group O negative is the universal donor, since its cells carry neither A nor B antigen.
Universal blood recipient group:
Group AB is the universal recipient, since its plasma carries no anti-A or anti-B antibody.
ABO blood group gene is located on chromosome:
The ABO gene sits on chromosome 9.
Element NOT found in blood in significant amounts:
Chromium is present only in traces. Iron, sodium and calcium are all found in significant amounts in blood.
A clot inside a vein/artery is called:
A clot formed inside a vessel is a thrombus. Once it breaks loose and travels, it becomes an embolus.
Number of bones in adult axial skeleton:
The axial skeleton, the skull, spine and rib cage, has 80 bones.
Number of bones in adult appendicular skeleton:
The appendicular skeleton, the limbs and their girdles, has 126 bones.
Number of vertebrae in the human spinal column (including fused sacrum/coccyx as single units):
The adult spine has 26 vertebrae, counting the fused sacrum and coccyx as one each.
Number of pairs of ribs:
There are 12 pairs of ribs.
Two long bones of the lower leg:
The tibia and fibula are the two long bones of the lower leg.
Over 99% of body calcium is found in:
Over 99 per cent of the body's calcium is locked in the bones and teeth.
Approximate weight of adult human brain:
An adult brain weighs about 1.3 to 1.4 kg.
Largest part of human brain:
The cerebrum is the largest part of the brain, about 85 per cent of its weight.
Voluntary actions are primarily controlled by:
Voluntary movement is initiated by the motor cortex. The cerebellum coordinates it.
Primary respiratory control centre is located in the:
The respiratory centre lies in the medulla oblongata, which is why an injury there stops breathing.
Body temperature is regulated by the:
The hypothalamus regulates body temperature, along with hunger, thirst and sleep.
The normal functioning of the nervous system is most directly affected by shortage of:
Sodium ions carry the nerve impulse along the axon, so a shortage disturbs the working of the nervous system.
Normal sex chromosomes in males:
Males have XY sex chromosomes.
Normal sex chromosomes in females:
Females have XX sex chromosomes.
Often called the 'master gland' of the body:
The pituitary is called the master gland, because its hormones control the other endocrine glands.
The gland that functions as both an endocrine and exocrine gland is the:
The pancreas is both endocrine and exocrine: it releases insulin into the blood and digestive juices into the intestine.
A key hormone produced by the pancreas that regulates blood sugar:
Insulin, from the beta cells of the pancreas, lowers blood sugar.
Iodine is mainly stored in and essential for the proper functioning of the:
Iodine is stored in the thyroid, which needs it to make the hormones thyroxine and triiodothyronine.
About the PPSC Everyday Science Past Paper 2021
Every MCQ above is taken from the Punjab Public Service Commission (PPSC) Everyday Science papers held in 2021, with the correct answer and a written explanation for each. Past-paper practice is the most dependable way to prepare for PPSC, FPSC, NTS, CSS and PMS, because these papers repeat their themes, and often the questions themselves, from one year to the next.
Questions were checked against reliable sources before publication. Where a circulating source sheet carried a factual or wording error, we corrected it rather than reproducing the mistake. For chapter-wise preparation, work through our Everyday Science MCQs hub, which also lists every other year’s paper. Further reading: Pakistan Movement and the PPSC official website.
How to Use This Paper
Attempt the full quiz before looking at any answer, then read the explanation for every question you got wrong, including those you guessed correctly. A past paper is only useful if you close the gaps it exposes. Pro members can download the complete paper as a PDF with all answers and explanations for offline revision.