✅ Correct Answer: 1) The angle between incident ray and emergent ray

🔍 Explanation:

When light passes through a prism, it bends (refracts) twice:

1. At the first surface (air to glass) — bends towards normal
2. At the second surface (glass to air) — bends away from normal

Due to this bending, the emergent ray is not in line with the incident ray.
The angle of deviation (δ) is defined as:
The angle between the direction of the incident ray and the emergent ray

So the correct answer is option 1.

✅ Correct Answer: 2) Serosa → Muscularis → Submucosa → Mucosa

🔍 Explanation:

The alimentary canal (digestive tract) wall is made up of four layers, arranged from outside to inside as follows:

1. Serosa – The outermost layer; a thin protective membrane (also called the visceral peritoneum).
2. Muscularis – Made of smooth muscles; responsible for peristalsis (movement of food).
3. Submucosa – A layer of connective tissue with blood vessels, nerves, and glands.
4. Mucosa – The innermost layer; it secretes mucus, digestive enzymes, and absorbs nutrients.

So the correct outer to inner sequence is:
Serosa → Muscularis → Submucosa → Mucosa

🔍Explanation
Loudness is how “loud” or “soft” a sound feels to our ears.
The Relationship: Loudness ∝ (Amplitude)²
This means:
Loudness is proportional to the square of the amplitude.
So if you double the amplitude, you don’t just double the loudness —
👉 you multiply it by 2² = 4.

🔍Explanation:
Bioluminescence is most prominently seen in Ctenophora (comb jellies) and some members of Coelenterata (like jellyfish).
Bioluminescence:- the production and emission of light by living organisms, is commonly observed in the marine environment, especially in deep-sea ecosystems.

🔍Explanation:
A lichen is a symbiotic relationship between an alga (phycobiont) and a fungus (mycobiont), making them a good indicator of pollution as they are sensitive to air quality, particularly sulfur dioxide levels.