Free Biodiversity and Variety of Life MCQs with Answers

1231. In sponges fertilization takes place which of the following?

• A. Ectoderm
• B. Endoderm
• C. Uterus
• D. Mesenchyme

Explanation: Choanocytes are cells of the mesenchyme, so fertilization occurs there.

1232. Which one is not a bony fish?

• A. Trout
• B. Sea horse
• C. Shark
• D. Tuna

Explanation: Sharks have skeleton made of cartilage and thus are not called "bony" fish. It is part of the chondrichthyes class of fishes.

1233. The animals that have features of both mammals and reptiles are?

• A. Duckbill platypus
• B. Spiny anteater
• C. Wolves
• D. Both A and B

Explanation: Monotremes are group of animals that lay eggs, and thus act as connecting feature between both mammals and reptiles. Duckbill platypus and spiny anteater are examples.

1234. Which of the following is not a bony fish?

• A. Perch
• B. Plaice
• C. Catfish
• D. Dogfish

Explanation: Dogfish is included in Chondrichthyes; it has a cartilaginous skeleton.

1235. Alternation of generation is absent in which coelentrate?

• A. Obelia
• B. Jellyfish
• C. Hydra
• D. Sea anemone

Explanation: Option C is correct since hydra only exhibits asexual reproduction by budding. As there is no sexually reproductive stage, alternation of generation is not possible. Alternation of a generation refers to the production of asexual form by sexual form and vice versa.Option A is incorrect since Obelia belongs to the class Hydrozoa in which both polypoid and medusoid forms show alternation of generation.Option B is incorrect since Jellyfish belongs to the class Scyphozoa and also consist of both sexual and asexual forms.Option D is incorrect since Sea Anemone also exhibits alternation of generation.

1236. Which of the following fish contained lungs?

• A. Lamprey
• B. Perch
• C. Plaice
• D. Dipnoi

Explanation: Option D is correct since the group, Dipnoi owes its name from the presence of two internal nostrils. Standing on the basic piscine platform, dipnoans show many interesting features that the early fishes have gone through to become land vertebrates, especially the amphibians. They are the link between fish and amphibians. Option A is incorrect since Lampreys are ancient fish that have characteristics similar to the first vertebrates. They do not have lungs and do not breathe air. Option B is incorrect since Perch and other fish have an organ called the swim bladder which has lost its connection to the digestive system. It specializes as a lung or breathing organ and can regulate the amount of gas that is in the bladder. Option C is incorrect since the plaice does not contain lungs.

1237. In some cases the blastomere can produce a complete embryo the cleavage will be?

• A. Spiral and determinate
• B. Spiral and indeterminate
• C. Radial and determinate
• D. Radial and indeterminate

Explanation: If a blastomere is capable of producing a complete embryo, then the cleavage would be considered indeterminate. In indeterminate cleavage, each blastomere has the potential to develop into a complete organism, even if it is separated from the other blastomeres. Indeterminate cleavage is typically found in organisms that undergo early embryonic cell divisions, such as many invertebrates and some vertebrates. If a blastomere is capable of producing a complete embryo, the cleavage can be either radial or spiral. Radial cleavage occurs when the cell divisions are parallel or perpendicular to the animal-vegetal axis of the embryo, resulting in cells that are more or less symmetrical.

1238. Excretory system of platyhelminthes consists of which of the following?

• A. Nephridia
• B. Flame cells
• C. Malpighian tubules
• D. Nephrons

Explanation: Platyhelminthes, also known as flatworms, do not have a true excretory system with specialized cells. Instead, they rely on simple diffusion across their body surface to eliminate metabolic wastes. Flatworms have a flattened body shape that allows for efficient gas and nutrient exchange across their body surface, but it also means that waste products can easily diffuse out of their body into the surrounding environment. This is possible because flatworms have a relatively simple body plan and a high surface area-to-volume ratio, which allows for efficient diffusion of gases and nutrients. In addition to simple diffusion, some flatworms have specialized flame cells that help to regulate the balance of water and salts in their body. Flame cells are specialized cells that are found in some flatworms, particularly those that live in freshwater environments. These cells have hair-like structures called cilia that move back and forth, creating a current that helps to remove excess water and metabolic wastes from the body.

1239. Enteron in coelenterates acts as which of the following

• A. Digestive cavity
• B. Body cavity
• C. Transporting cavity
• D. All of these

Explanation: The enteron is the space which acts as the body cavity for all general functions.

1240. Alternation of generation is absent in which coelenterate?

• A. Obelia
• B. Jelly fish
• C. Hydra
• D. Sea anemone

Explanation: Alteration of generation refers to the alteration between the methods of reproduction, from sexual to asexual. It does not occur in hydra as it only reproduces by budding, asexual reprouction.