Free Biodiversity and Variety of Life MCQs with Answers

1241. The sperms are what in origin?

• A. Ectodermal
• B. Mesodermal
• C. Endodermal
• D. None of these

Explanation: Option B is correct since the sperm and egg cells are produced from the germs cells- spermatozoa and oogonium present inside the 'testes' and 'ovaries' respectively. Since the 'gonads' and the 'germ cells' have a mesodermal origin, sperm and egg cells also have a mesodermal origin. sperm cells are derived from germ cells, which in turn are formed from the mesodermal layer of the developing embryo. Sperm cells are not derived from the ectoderm or endoderm.

1242. Which of the following are believed to have common origin with 'Annelids'?

• A. Nematods
• B. Arthropods
• C. Molluscs
• D. None of these

Explanation: Option B is correct since it is believed that 'arthropods' and 'annelids' have a common origin as they both have appendages, a segmented body, and a cuticle.

1243. The canal system in sponges develop due to which of the following?

• A. Porous walls
• B. Gastrovascular system
• C. Reproduction
• D. Folding of inner walls

Explanation: Canal system is also known as aquiferous system. The canal system of sponges helps in food acquisition, respiratory gas exchange and also in excretion. It occurs by folding of inner walls to provide maximum surface area, as seen in the image below.

1244. Nephridia are the excretory organs of members of which phylum?

• A. Arthropoda
• B. Cnidaria
• C. Annelida
• D. Mollusca

Explanation: Nephridia are the excretory organs present in annelids such as earthworm. Flatworms, cephalochordate, rotifers contain protonephridia or flame cells for osmoregulation.

1245. Nervous system of nematodes consists of which of the following?

• A. Ventral nerve cord
• B. Dorsal nerve cord
• C. Lateral nerve cord
• D. All of these

Explanation: d) All of these, Explanation: The correct answer is d) All of these. Nematodes' nervous system consists of a ventral nerve cord, lateral nerve cords, and other interconnected nerve structures that allow them to sense their environment, coordinate movements, and carry out various essential functions.

1246. Flame cells are excretory structures for which of the following?

• A. Annelida
• B. Coelenterates
• C. Echinodermata
• D. Platyhelminthes

Explanation: Correct Option:D This option is correct because flame cells are the specialized cells found in platyhelminthes including flatworm rotifer and nemerteans. These are the simplest animals to have a dedicated excretory system.Flame cell function like a kidney in removing waste materials from the body.

1247. Which of the folowing system is not well developed in acoelomates?

• A. Excretory
• B. Nervous
• C. Transport
• D. Both A and B

Explanation: Acoelomates commonly possess a simple digestive tract, nervous system, and excretory system.

1248. Carapace is present in which class of arthropods?

• A. Arachnids
• B. Insects
• C. Crustaceans
• D. All of these options are correct

Explanation: The term "carapace" refers to a hard, protective outer shell or plate that covers the body of some arthropods. Out of the given options, carapace is present in crustaceans. Crustaceans are a large class of arthropods that includes animals such as crabs, lobsters, shrimp, and crayfish, which all have a carapace covering their bodies.

1249. Which of the following is non-cellular in animals in most cases?

• A. Chlorenchyma
• B. Mesoderm
• C. Sclerenchyma
• D. Mesenchyme

Explanation: Mesenchyme is non-cellular in animals in most cases. Mesenchyme is embryonic connective tissue that is made up of loosely arranged, unspecialized cells. These cells differentiate into various types of connective tissues, such as bone, cartilage, and muscle.

1250. The second largest phylum of invertebrates is which of the following?

• A. Porifera
• B. Arthropoda
• C. Chordata
• D. Mollusca

Explanation: Molluscs are the second largest phylum of invertebrates after arthropods.