Respiration

Step 1: Understanding Cockroach Respiration
- Cockroaches have ten pairs of spiracles, but only the first two pairs (thoracic spiracles) function in inspiration.
- The remaining eight pairs (abdominal spiracles) function in expiration.

- Gomphoses are specialized joints in which a peg fits into a socket, such as the joint between teeth and the alveolar socket in the jaw.
- Syndesmoses are fibrous joints where bones are connected by a ligament, such as the distal tibiofibular joint.
- Sutures are immovable joints found in the skull.
- Synchondroses are cartilaginous joints where bones are connected by hyaline cartilage.

Step 1: In the anaerobic respiration pathway, glucose is first converted into pyruvic acid. Then, depending on the pathway, pyruvic acid may undergo fermentation to form ethanol or lactic acid. Therefore,
- A = Glucose (starting molecule of anaerobic respiration).
- B = Pyruvic acid (intermediate product).
- C = Ethanol or Lactic acid (products of fermentation).
- D = Lactic acid (when fermentation leads to lactic acid).

Step 1: Understanding the Mechanism of Inspiration
- During inspiration, the diaphragm contracts (not relaxes), increasing thoracic volume.
- The rib cage and sternum move upward, expanding the thoracic cavity.
- Reason (R) is incorrect since diaphragm relaxation leads to expiration.

Here’s the correct matching of concepts with their corresponding scientists:
- A) Behaviour of chromosomes was parallel to the behaviour of genes: This idea is associated with Sutton & Boveri (IV). They proposed the chromosomal theory of inheritance, suggesting that genes are located on chromosomes and follow the same principles of inheritance as chromosomes.
- B) Rediscovery of Mendel’s experiments: This is associated with Correns (III), who, along with other scientists, rediscovered Mendel’s laws of inheritance in the early 20th century.
- C) Distance between genes on chromosome: This concept is associated with Alfred Sturtevant (II), who used gene mapping techniques and showed that the relative distances between genes on chromosomes could be measured.
- D) Mutations: This is associated with Hugo de Vries (I), who is famous for his work on mutations and the theory of mutation as a cause of evolution. Thus, the correct matching is:
- A) Sutton & Boveri → Behaviour of chromosomes was parallel to the behaviour of genes.
- B) Correns → Rediscovery of Mendel’s experiments.
- C) Alfred Sturtevant → Distance between genes on chromosome.
- D) Hugo de Vries → Mutations.

- Statement I is false because neuston refers to organisms that live on the surface of water, not those that swim in it.
- Statement II is true, as decomposers can indeed be found in the limnetic zone of water bodies, particularly in the upper layers where light penetrates.