All Free Biology MCQs with Answers

1131. Melanin pigment in cockroach is found in__________?

• A. Epicuticle
• B. Exocuticle
• C. Endocuticle
• D. All of these

Explanation: Melanin is deposited mainly in the pigmented exocuticle, the harder layer beneath the epicuticle, giving the cockroach cuticle its dark colour. The epicuticle is mainly a thin waterproofing layer, while the endocuticle is softer and generally lacks the same pigmentation.

1132. Chitin in cockroach is absent in____________?

• A. Epicuticle
• B. Exocuticle
• C. Endocuticle
• D. All of these

Explanation: The epicuticle is the outermost thin, waxy layer of the cockroach cuticle and lacks chitin; its lipids help reduce water loss. The exocuticle and endocuticle are the main chitin-containing layers, so choosing either of them reverses the cuticle’s structure.

1133. In many which phylum the body of an organisms is usually divided in there regions called head, thorax and abdomen?

• A. Arthropods
• B. Chordata
• C. Annelida
• D. Echinodermata

Explanation: In many arthropods, the body is divided into head, thorax and abdomen, especially in insects. Annelids may show segmentation but do not characteristically have these three named regions, which makes arthropods the best fit.

1134. In all arthropods,the body is covered with a chittinous cuticle which is secreted by the____________?

• A. Endodermis
• B. Mesophyll
• C. Chitin
• D. Epidermis

Explanation: The chitinous cuticle of an arthropod is secreted by the underlying epidermal cells. Chitin is the material being secreted, not the secreting tissue, while endodermis and mesophyll are plant tissue terms.

1135. In mouth cavity of many molluscs there is a rasping tongue like structure_________provided with many horny teeth.

• A. Ligule
• B. Radula
• C. Mantle
• D. Muscle

Explanation: The radula is a rasping, tongue-like ribbon bearing many horny teeth, used by most molluscs to scrape or cut food. The mantle is a tissue covering the visceral mass, whereas a ligule and muscle are not the characteristic toothed feeding structure.

1136. Snails belong to__________?

• A. Cephalopodsxc
• B. Gastropods
• C. Bivalves
• D. Athropods

Explanation: Snails are gastropod molluscs, a group characterised by a distinct head, muscular foot and usually a single coiled shell. Cephalopods include squid and octopuses, while bivalves include clams and oysters; choosing cephalopods confuses different molluscan classes.

1137. It is stiff rod of special cells surrounded by connecive tissue present in the mid -dorsal region and appears in the embryos of all chordates

• A. Placenta
• B. Notochord
• C. Cranianta
• D. Ligule

Explanation: The notochord is a flexible supporting rod lying along the mid-dorsal side of chordate embryos and is surrounded by connective tissue. The cranium is a skull structure, whereas the placenta supports exchange between a mother and embryo; students may choose placenta because both occur during development.

1138. The phylum chrordata comprise about how many species?

• A. 25,000
• B. 50,000
• C. 100,000
• D. 10,00,000Educational Resources

Explanation: Traditional biology texts commonly give approximately 50,000 living species in the phylum Chordata, including tunicates, lancelets and vertebrates. The figure 100,000 may seem reasonable because vertebrates are diverse, but it overestimates the usual textbook count for the whole phylum.

1139. Sub- phylum vertebrate is also known as__________?

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

Explanation: Vertebrates are also called Craniata because they possess a cranium surrounding the brain. Pisces, Aves and Amphibia are names for particular vertebrate groups, so choosing Pisces wrongly treats all vertebrates as fishes.

1140. They are considered to be the most primitive and are surely the first of the vertebrates?

• A. Frogs
• B. Reptiles
• C. Amphibinas
• D. Jawless fishes

Explanation: Jawless fishes, such as lampreys and hagfishes, retain primitive vertebrate features and lack jaws. Frogs and other amphibians appeared later in vertebrate evolution, so choosing amphibians confuses the first land vertebrates with the earliest vertebrate group.