Consider statements about environment: 1. The greenhouse effect is entirely unnatural. 2. Deforestation contributes to global warming. 3. Ozone depletion causes skin cancer. Which are correct? MCQ with Answer and Explanation

Explanation:
Fucoxanthin is a carotenoid pigment found in brown algae (Phaeophyceae) that gives them their characteristic brown or olive-green color, masking the green chlorophyll. Phycoerythrin is red (red algae), phycocyanin blue (cyanobacteria, some red algae). Brown algae include kelps and Fucus.

Explanation:
The Miller-Urey experiment (1953) simulated the conditions of the primitive Earth's atmosphere (methane, ammonia, hydrogen, and water vapor) in a closed system and applied electrical sparks to simulate lightning. After a week, they found that several organic compounds, including amino acids (the building blocks of proteins), had been synthesized, supporting the theory of chemical evolution.

Explanation:
Plasmodesmata are microscopic channels that traverse the cell walls of plant cells, enabling the transport of water, ions, molecules, and even some viruses between them, thus ensuring cytoplasmic continuity. Gap junctions perform a similar function in animal cells, while tight junctions and desmosomes are for sealing and adhesion, respectively.