100 most important General Science (Zoology) questions with answers for UPSC, SSC, Railways, and other competitive exams:

General Zoology

Study of animals?

– Zoology

Study of insects?

– Entomology

Father of Zoology?

– Aristotle

Smallest living unit of an organism?

– Cell

Basic structural unit of bones?

– Osteon

Study of fish?

– Ichthyology

Study of birds?

– Ornithology

Study of amphibians and reptiles?

– Herpetology

Study of mammals?

– Mammalogy

Science of classification?

– Taxonomy

Animal Classification

Largest phylum of the animal kingdom?

– Arthropoda

Phylum of humans?

– Chordata

Group of animals with backbones?

– Vertebrates

Animals without backbones?

– Invertebrates

Phylum of sponges?

– Porifera

Phylum of jellyfish?

– Cnidaria

Phylum of starfish?

– Echinodermata

Phylum of flatworms?

– Platyhelminthes

Phylum of earthworms?

– Annelida

Class of amphibians?

– Amphibia

Human Body and Physiology

Largest organ in the human body?

– Skin

Smallest bone in the body?

– Stapes

Longest bone in the body?

– Femur

Red blood cells are formed in?

– Bone marrow

Iron-containing pigment in blood?

– Hemoglobin

Largest artery in the body?

– Aorta

Functional unit of the kidney?

– Nephron

Basic unit of the nervous system?

– Neuron

Part of the brain responsible for balance?

– Cerebellum

Hormone that regulates blood sugar?

– Insulin

Reproduction and Development

Cell formed after fertilization?

– Zygote

Process of cell division in gametes?

– Meiosis

Process of asexual reproduction in amoeba?

– Binary Fission

Oviparous animals lay?

– Eggs

Viviparous animals give birth to?

– Young ones

Human pregnancy duration?

– 9 months

Male reproductive cell?

– Sperm

Female reproductive cell?

– Ovum

Hormone responsible for male characteristics?

– Testosterone

Hormone responsible for female characteristics?

– Estrogen

Blood and Circulatory System

Blood group called universal donor?

– O Negative

Blood group called universal recipient?

– AB Positive

Liquid part of blood?

– Plasma

Protein that helps in blood clotting?

– Fibrinogen

Component that carries oxygen in blood?

– Hemoglobin

Largest vein in the human body?

– Vena Cava

Heart chamber that pumps oxygenated blood?

– Left Ventricle

Heart chamber that receives deoxygenated blood?

– Right Atrium

Number of chambers in the human heart?

– Four

Blood vessel carrying oxygenated blood from the lungs?

– Pulmonary Vein

Digestive System

Largest gland in the human body?

– Liver

Enzyme that digests proteins?

– Pepsin

Organ that stores bile?

– Gallbladder

Acid found in the stomach?

– Hydrochloric Acid

Organ responsible for nutrient absorption?

– Small Intestine

Organ that removes toxins from blood?

– Liver

Digestive juice produced by the pancreas?

– Pancreatic Juice

End product of carbohydrate digestion?

– Glucose

End product of protein digestion?

– Amino Acids

End product of fat digestion?

– Fatty Acids

Respiratory System

Main organ of respiration?

– Lungs

Gas used by the body in respiration?

– Oxygen

Gas expelled from the body during exhalation?

– Carbon Dioxide

Voice box in humans?

– Larynx

Organ that prevents food from entering the windpipe?

– Epiglottis

Smallest air sacs in the lungs?

– Alveoli

Pigment responsible for oxygen transport?

– Hemoglobin

Muscle that helps in breathing?

– Diaphragm

Total number of lungs in the human body?

– Two

Process of breathing out?

– Exhalation

Nervous System and Sense Organs

Largest part of the brain?

– Cerebrum

Part of the brain controlling heartbeat?

– Medulla Oblongata

Number of cranial nerves in humans?

– 12 pairs

Receptor cells in the eyes for color vision?

– Cones

Receptor cells in the eyes for night vision?

– Rods

Fluid in the inner ear for balance?

– Endolymph

Smallest muscle in the human body?

– Stapedius

Outer covering of the eye?

– Cornea

Sense organ responsible for smell?

– Nose

Sense organ responsible for taste?

– Tongue

Excretory and Endocrine System

Main excretory organ?

– Kidney

Hormone regulating metabolism?

– Thyroxine

Hormone secreted by adrenal glands?

– Adrenaline

Hormone responsible for growth?

– Growth Hormone

Waste product removed by the kidneys?

– Urea

Hormone regulating sleep cycle?

– Melatonin

Diabetes is caused by deficiency of?

– Insulin

Disease caused by iodine deficiency?

– Goiter

Master gland of the body?

– Pituitary Gland

Gland responsible for calcium balance?

– Parathyroid

Miscellaneous Zoology

Fastest land animal?

– Cheetah

Largest mammal?

– Blue Whale

Flightless bird?

– Ostrich

Bird that can fly backward?

– Hummingbird

Animal with the longest lifespan?

– Tortoise

Largest freshwater fish?

– Beluga Sturgeon

Reptile with the strongest bite force?

– Crocodile

Animal known as the ship of the desert?

– Camel

Insect that causes malaria?

– Anopheles Mosquito

Largest living amphibian?

– Chinese Giant Salamander