All Free Biology MCQs with Answers

• A. Mytilus
• B. Chaetopterus
• C. Penguin
• D. Jellyfish

Explanation: Deuterostomes are a group of animals characterized by their embryonic development, where the anus forms before the mouth.

• A. Protozoa
• B. Parazoa
• C. Metazoa
• D. Aves

Explanation: Porifera, commonly known as sponges, belong to the subkingdom Parazoa within the kingdom Animalia.

• A. Pisces
• B. Amphibia
• C. Reptilia
• D. Aves

Explanation: The correct answer is Aves. Female birds generally possess a single ovary on the left side of their body, an adaptation believed to…

• A. Flying mammals
• B. Flesh-eating mammals
• C. Hoofed mammals
• D. Aquatic mammals

Explanation: Chiroptera, commonly known as bats, are the only flying mammals. Their wings are composed of a thin membrane of skin supported by…

• A. Desert-snake
• B. Coelenterate
• C. A big-reptile
• D. Black-forest monkey

Explanation: The Portuguese-man-of-war is a coelenterate, a marine invertebrate belonging to a group that includes jellyfish and sea anemones.

• A. One ventricle, two atria
• B. Two ventricles, one atrium
• C. One ventricle, one atrium
• D. One ventricle, one atrium, one sinus venosus

Explanation: Amphibians typically have a heart with three chambers, which includes one ventricle and two atria.

• A. Ornithology
• B. Ichthyology
• C. Herpetology
• D. Serpetology

Explanation: The correct answer is Ichthyology, which is the scientific study of fishes, including their biology, classification, and conservation.

• A. Bipinnaria larva
• B. Trochophore larva
• C. Glochidium larva
• D. Instar larva

Explanation: Tornaria larva resembles with Bipinnaria larva. Because Tornaria larva of hemichordates and Bipinnaria of Echinodermata are very similar…

• A. Myxine (Hagfish)
• B. Skates
• C. Sharks
• D. Teleost (Bony Fishes)

Explanation: Marine teleosts are hypoosmotic to seawater, so they face osmotic loss of water and diffusional gain of NaCl across the gill.

• A. Class cyclostomata
• B. Class osteichthyes
• C. Class chondricthyes
• D. Ceplialochordate

Explanation: Placoid scales are a unique type of scales that are present in cartilaginous fishes like sharks and rays.

• A. Crocodile
• B. Frog
• C. Tiger
• D. Pigeon

Explanation: In the case of a pigeon, the gizzard is the part of their digestive system that helps with crushing and grinding food.

• A. Cattle
• B. Tumefaciens
• C. Human
• D. Termite

Explanation: Trichonympha is a tiny organism that lives inside the digestive tract of termites.

• A. Habituation
• B. Imprinting
• C. Operant learning
• D. Insight learning

Explanation: Imprinting is a behavior in which a young animal forms an attachment to another organism or object during a critical period early in life.

• A. Cartilaginous fishes
• B. Bony fishes
• C. Cyclostomes
• D. Both (A) & (B)

Explanation: Hagfish, also known as cyclostomes, are a type of jawless fish. They have a unique anatomy and behavior compared to cartilaginous fishes…

• A. Annelida
• B. Arthropoda
• C. Chordata
• D. Coelenterata

Explanation: The largest phylum of animals is the phylum Arthropoda. It includes insects, spiders, crustaceans, and other joint-legged organisms.

• A. cellulose
• B. chitin
• C. murein
• D. hemi-cellulose

Explanation: Option B is correct. Chitin is found in the exoskeleton of crabs. Chitin is a tough, fibrous material that is made up of long chains of…

• A. Apothecium
• B. Perithecium
• C. Hysterothylacium
• D. Cleistothecium

Explanation: The correct answer is Apothecium. An apothecium is a cup-shaped ascocarp with an exposed hymenium.

• A. Alternaria_solani
• B. Phytophthora_infestans
• C. Erysiphe_graminls
• D. Claviceps_purpurea

Explanation: Alternaria solani is the correct answer as it is the fungal pathogen responsible for early blight of potato, causing specific symptoms on…

• A. Athletes foot
• B. Ringworm
• C. Dandruff
• D. Ergot

Explanation: Microsporum furfur is a type of fungus that is associated with the condition known as dandruff.

• A. Facultative saprophyte
• B. Facultative parasite
• C. Obligate saprophyte
• D. Obligate parasite

Explanation: Saprophytic is the mode of nutrition in which organisms feed on dead and decayed matter, a facultative saprophyte ia a mainly parasitic…