All Free Biology MCQs with Answers

1351. Of the following which one has glassy shells________________?

• A. Radiolarians
• B. Forams
• C. Both of these
• D. None of these

Explanation: Radiolarians have delicate, glass-like skeletons made mainly of silica, giving them a transparent or glassy appearance. Foraminiferans usually possess shells made of calcium carbonate, so their shells are not described as glassy. Students may choose both by confusing the mineral shells of these two protist groups.

1352. The only group of algae having no flagellated motile cells at any stage is___________?

• A. Chrysophyta
• B. Phaeophyta
• C. Pyrrophyta
• D. Rhodophyta

Explanation: Rhodophyta are the only major algal group in which flagellated motile cells are absent throughout the life cycle. Students may choose Phaeophyta because some brown algae have non-motile stages, but brown algae do produce flagellated gametes or zoospores. The submitted key matches.

1353. Chalk is gradually formed of dead______________?

• A. Actinopods
• B. Foraminiferans
• C. Apicomplexans
• D. Radiolarians

Explanation: Chalk is formed largely from accumulated calcium carbonate shells of dead foraminiferans, microscopic marine protists. Students may choose radiolarians because they also form abundant marine fossils, but radiolarian skeletons are mainly silica and contribute to siliceous deposits rather than chalk. The submitted key matches.

1354. Brown algae are also known as___________?

• A. Phaeophyta
• B. Rhodophyta
• C. Pyrrophyta
• D. Chrysophyta

Explanation: Brown algae belong to the phylum Phaeophyta, whose brown colour is mainly due to the carotenoid pigment fucoxanthin masking chlorophyll. Students may choose Rhodophyta because it is another major algal group, but Rhodophyta are red algae. The submitted key matches.

1355. The drfinite shape to ciliates is given by____________?

• A. Pellicle
• B. Penicle
• C. Calcium
• D. Cell wall

Explanation: A pellicle is a firm but flexible protein-rich covering beneath the cell membrane of ciliates, and it maintains their definite shape while allowing movement. Students may choose a cell wall because walls also provide shape in many organisms, but ciliates do not have a typical cellulose cell wall. The submitted key matches.

1356. Golden algae are also known as___________?

• A. Chrysophyta
• B. Phaeophyta
• C. Pyrrophyta
• D. Rhodophyta

Explanation: Golden algae are classified in Chrysophyta, and their golden colour is associated with carotenoid pigments such as fucoxanthin. Students may choose Phaeophyta because brown algae also contain fucoxanthin, but their characteristic colour and group name are different. The submitted key matches.

1357. Complex specialized flagellates living symbiotically in the gut of termites are___________?

• A. Trichonymphas
• B. Trypanosoma
• C. Euglena
• D. Radiolarians

Explanation: Trichonympha are complex flagellated protists that live symbiotically in the intestines of termites, where they help digest cellulose. Students may choose Euglena because it is also a flagellate, but Euglena is free-living and photosynthetic or mixotrophic rather than a termite-gut symbiont. The submitted key matches.

1358. Based on molecular data euglenoids are thought to be closely related to___________?

• A. Dinoflagellates
• B. Zooflagellates
• C. Protozoans
• D. Algae

Explanation: Molecular evidence has traditionally placed euglenoids close to zooflagellates, particularly because of shared flagellated and cellular features in older classification systems. Students may choose algae because many euglenoids photosynthesize, but photosynthesis alone does not establish their closest evolutionary relationship. The submitted key matches.

1359. Stentor is a/an____________?

• A. Ciliate
• B. Foraniniferan
• C. Actinopods
• D. Apicomplexan

Explanation: Stentor is a trumpet-shaped ciliate covered with cilia and uses them to create water currents that bring food toward its oral region. Students may choose an actinopod because both are unicellular protists, but actinopods have radiating axopodia rather than the cilia characteristic of Stentor. The submitted key matches.

1360. All phostosynthetic euglenoids lose their chlorophyll when grown in dark and obtain their nutrients heterotrophically this statement is___________?

• A. True
• B. False
• C. May be true may be false
• D. Unpredictable

Explanation: The statement is false because it uses the absolute word all, whereas not every photosynthetic euglenoid necessarily loses its chlorophyll in darkness; the response varies among species and conditions. Students may choose true by recalling that Euglena can become colourless and feed heterotrophically in darkness, but that observation cannot be extended to every photosynthetic euglenoid. The submitted key matches.