Consider statements about ecology: 1. Producers form the first trophic level. 2. Energy flow in an ecosystem is unidirectional. 3. The pyramid of energy can be inverted. Which are correct? MCQ with Answer and Explanation

Explanation:
Cholera, caused by Vibrio cholerae, produces cholera toxin that stimulates massive secretion of water and electrolytes into the intestinal lumen, leading to profuse, watery diarrhea resembling rice water, causing rapid dehydration. Treatment is oral rehydration therapy and antibiotics. Typhoid causes fever, dysentery causes bloody stools.

Explanation:
The rough endoplasmic reticulum (RER) has ribosomes attached to its cytoplasmic surface, making it appear rough, and is primarily involved in protein synthesis and modification. The smooth endoplasmic reticulum (SER) lacks ribosomes and is the major site for lipid synthesis and detoxification of drugs. Statement 3 is incorrect as detoxification is a function of SER.

Explanation:
Chlorophyll a is the primary photosynthetic pigment found in all algae and is essential for the light reactions of photosynthesis. Different groups of algae also contain other accessory pigments like chlorophyll b, c, phycobilins (phycocyanin, phycoerythrin), and carotenoids (fucoxanthin), which give them their characteristic colors (green, red, brown) and help in capturing light energy.