All Free Biology MCQs with Answers

1141. Scolidon or dog fish belong to the group of fishes called__________?

• A. Cartilaginous fishes
• B. Bony fishes
• C. Running fishes
• D. Jawless fishes

Explanation: Scoliodon, or dogfish, has a skeleton made mainly of cartilage, so it belongs to the cartilaginous fishes. Bony fishes have an ossified skeleton, and dogfish are not jawless because they possess functional jaws; students may choose bony fishes because most familiar fishes are bony.

1142. Vascular Cambium initially appears as actively dividing cells between_________________?

• A. Primary Xylem and secondary xylem.
• B. Primary xylem and secondary phloem.
• C. Primary xylem and primary phloem
• D. Secondary xylem and secondary phloem.

Explanation: In a young dicot stem, vascular cambium first develops from dividing cells between the primary xylem and primary phloem, forming a cambium ring. Option b is a likely mistake because secondary xylem and secondary phloem are produced only after the vascular cambium becomes active.

1143. An increrase in plant girth due to activity of _____________ is called secondary growth?

• A. Cork cambium
• B. Pith.
• C. Vascular cambium.
• D. Both a and c

Explanation: Secondary growth increases stem or root girth through the vascular cambium, which forms secondary xylem and phloem, and the cork cambium, which forms protective periderm. Since both cambiums contribute, option d is correct; choosing only option c ignores the contribution of cork cambium.

1144. Among the followings which is the most longest supportive cell?

• A. Tracheids
• B. Sclereids
• C. Trachea
• D. Collenchyma cells

Explanation: Tracheids are long, narrow, lignified cells that provide both support and water conduction, and they are generally more elongated than sclereids or collenchyma cells. Option c, trachea, is a likely choice because it sounds similar to tracheids, but trachea is not the correct name for an individual plant support cell.

1145. Secondary cell wall of sclerenchyma cells is impregnated with_________________?

• A. Cellulose.
• B. Peptidoglycan and murein.
• C. Lignin.
• D. Pectin.

Explanation: Sclerenchyma cells have thick secondary walls impregnated with lignin, making them hard and mechanically strong after maturity. Cellulose is also present in the wall, so option a may seem attractive, but lignin is the characteristic strengthening impregnation.

1146. Which of the following plays the major role in providing support to young herbaceous parts of the plant?

• A. Living cells of epidermis with higher turgor pressure.
• B. Living cells of cortex and pith with higher turgor pressure.
• C. Collenchyma cells
• D. All of these

Explanation: Young herbaceous organs receive support from turgid living cells in the epidermis, cortex and pith, while collenchyma provides additional flexible mechanical support. Since all listed tissues contribute, option d is correct; choosing only collenchyma overlooks the important role of cell turgor.

1147. Hornwarts are included in sub-class of __________?

• A. Anthoceropsida
• B. Bryopsida
• C. Hepaticopsida
• D. Psilopsida

Explanation: Hornworts are placed in the class Anthoceropsida, characterised by a horn-like sporophyte that grows from the gametophyte. A common mistake is Bryopsida, but that class contains true mosses such as Funaria.

1148. Bryophtes are called amphiabians of plant world because:

• A. Bryophytes like amphibian ancestors are one of the most primitive organisms in this world.
• B. Bryophytes like amphibian live in damp shady places and close to water body.
• C. Amphibians have close relation with bryophytes in their habitat.
• D. All of these

Explanation: Bryophytes are called the amphibians of the plant kingdom because they live on land but require damp conditions or water for the movement of sperm to the egg. The likely alternative is “all of these,” but the statement about a close evolutionary or habitat relationship with amphibians is not the reason for this term.

1149. Equistem is an example of___________?

• A. Psilopsida
• B. Lycopsida
• C. Sphenopsida
• D. Prteropsida

Explanation: Equisetum belongs to Sphenopsida, also called the horsetail group, whose stems commonly have distinct nodes and internodes. Lycopsida is a separate group containing club mosses such as Selaginella.

1150. Which of the following tracheophytes are also called arthrophytes______________?

• A. Psilopsids
• B. Lycopsids
• C. Sphenopsids
• D. Prteropsids

Explanation: Sphenopsids are called arthrophytes because their jointed, ribbed stems have conspicuous nodes and internodes, as seen in Equisetum. The likely confusion is with lycopsids, which are characterised by small leaves called microphylls rather than jointed stems.