Neural Control And Coordination

Step 1: Understanding Neurotransmitter Effects

- Cocaine blocks dopamine reuptake, leading to prolonged stimulation of the brain's reward system.
- Charas, Heroin, and Morphine affect other neurotransmitters like endorphins and opioids, but not dopamine transport.

Step 1: Recall Spinal Nerve Counts:
Humans have 31 pairs of spinal nerves:

• Cervical nerves (C): 8 pairs ( ). Note: There are 7 cervical vertebrae but 8 nerves.
• Thoracic nerves (T): 12 pairs ( ).
• Lumbar nerves (L): 5 pairs ( ).
• Sacral nerves (S): 5 pairs ( ).
• Coccygeal nerves (Co): 1 pair ( ).

Step 2: Matching:

• A. Cervical nerves V. 8 pairs.
• B. Thoracic nerves III. 12 pairs.
• C. Lumbar nerves I. 5 pairs.
• D. Coccygeal nerves II. 1 pair.

Step 3: Conclusion:
The sequence is A-V, B-III, C-I, D-II. Matches Option (A).

Step 1: Analyze Statement I:
Salmon and Hilsa are marine fishes that migrate up rivers to spawn in fresh water. This migration from Sea to River is called Anadromous migration. Catadromous migration (River to Sea) is seen in fishes like the Eel (\Anguilla). Thus, Statement I is False.
Step 2: Analyze Statement II:
The Limnetic zone refers to the open, well-lit surface waters of a lake, away from the shore. This is the primary zone of production where photosynthesis (P) by phytoplankton typically exceeds respiration (R) (i.e., ). The point where is specifically called the compensation depth, which marks the lower boundary of the euphotic zone, but the limnetic zone as a whole is a net producer. Therefore, stating that P and R are equal in the limnetic zone is generally False (except at the specific compensation boundary).
Step 3: Conclusion:
Since both statements are factually incorrect, Option (B) is the appropriate answer.

Step 1: Analyze Drug Effects:

• Cocaine: A strong stimulant derived from \Erythroxylum coca. It increases dopamine levels. Standard biology textbooks (e.g., NCERT) specifically state that "Excessive dosage of cocaine causes hallucinations."
• Morphine & Heroin: These are opioids/depressants. They slow down body functions and act as analgesics or sedatives, not primarily as hallucinogens.
• Ganja (Cannabis): While cannabinoids are known hallucinogens, the specific phrasing "Excessive consumption... causes hallucinations" is the classic textbook description for Cocaine toxicity.

Step 2: Conclusion:
In the context of competitive exams and standard texts, Cocaine is the intended answer for drug-induced hallucinations at high dosages.

Step 1: Analyze the Conservation Status of Each Species:
We need to identify species that are considered threatened (Endangered, Vulnerable, etc.) or are of significant conservation concern in India.

• I. \Corvus splendens (House Crow): Abundant, Least Concern (LC).
• II. \Panthera tigris (Bengal Tiger): Endangered (EN). Highly protected under Wildlife Protection Act (Schedule I).
• III. \Oryctolagus cuniculus (European Rabbit): Domesticated/Least Concern.
• IV. \Antelope cervicapra (Blackbuck): Near Threatened (NT). Protected under Schedule I of WPA, 1972. Historically threatened by hunting.
• V. \Loris tardigradus (Slender Loris): Endangered (EN).
• VI. \Macaca mullata (Rhesus Macaque): Least Concern (LC).

Step 2: Select the Group:
The group containing the species of high conservation concern is II (Tiger), IV (Blackbuck), and V (Slender Loris). The other lists contain common animals like Crows and Rabbits.
Step 3: Final Answer:
The correct combination is II, IV, V.

UV-B and UV-C rays are more energetic than UV-A and can damage DNA and proteins. Phototaxis is movement toward (positive) or away (negative) from light. Both statements are accurate.

Concept: Sacred groves are patches of natural vegetation protected by religious and cultural traditions, acting as in-situ conservation sites.
Explanation: Seshachalam hills (Andhra Pradesh) and Papi Kondalu (Andhra Pradesh/Telangana) are recognized regions in India with significant sacred groves.

• **Foramen of Monro (Foramen Manro)** — this is the interventricular foramen connecting lateral ventricles to the third ventricle (brain structure) — corresponds to II.
• **Ductus (Aqueduct) of Sylvius** — the cerebral aqueduct connecting the third and fourth ventricles — a brain/ventricular structure — corresponds to IV.
• **Metacoel** is a term sometimes used in comparative anatomy for body cavity divisions (not a standard brain structure) — its inclusion makes the option set ambiguous.
• **Foramen ovale** and **foramen magnum** are skull foramina (openings in the skull) rather than intrinsic brain cavities; **ductus arteriosus** is a cardiac fetal vessel.
• Because only II and IV clearly refer to intracranial ventricular structures, none of the choices list just II & IV — the closest provided choice is (3) which adds VI (Metacoel) and therefore the question as printed is ambiguous.
• Best possible pick from the given options: (3) II, IV, VI with the note that VI is not a typical brain part and the question appears imprecise.

Concept: Heroin (diacetylmorphine) is a semi-synthetic opioid drug.
Explanation: Heroin is synthesized by acetylating the natural alkaloid morphine, which is extracted from the opium poppy ({Papaver somniferum}).

Cerebrum = memory & communication; Hypothalamus = thermoregulation; Superior colliculi = vision; Pons = pneumotaxic centre regulating respiration.

Amphetamines are central nervous system stimulants and can cause insomnia and sleeplessness. Barbiturates and tranquilizers are sedatives; Lysergic acid diethyl amide (LSD) causes hallucinations but not primary sleeplessness.

Concept: This tests two ecological and physiological principles.
Explanation: Statement I is **True**: **Cyclomorphosis** is the phenomenon of cyclic changes in body form in response to seasonal environmental changes, common in zooplankton. Statement II is **False**: The principle that a temperature increase doubles the metabolic rate is the **effect** (or Van't Hoff's rule). **Allen's rule** relates to the size of extremities (limbs, ears) in endotherms in relation to climate.

In-situ conservation refers to the protection of species in their natural habitats. Examples include Sanctuaries, Sacred groves, and National parks. Ex-situ conservation involves outside habitats, e.g., Cryopreservation, Gene banks, and In-vitro culture. Hence, correct in-situ methods are I, III, V.

Concept: Sacred groves are patches of natural vegetation protected by religious and cultural traditions, acting as in-situ conservation sites.
Explanation: Seshachalam hills (Andhra Pradesh) and Papi Kondalu (Andhra Pradesh/Telangana) are recognized regions in India with significant sacred groves.