Environmental Science

Step 1: Understand the origin of the term 'biodiversity.'
The term "biodiversity" was first proposed by W.G.Rosen in 1985 to describe the variety of life on Earth.
Step 2: Analyze the options.
Hooker, Candolle, and Radford were prominent biologists, but none of them coined the term "biodiversity."
W.G.Rosen was the one who first used the term in the context of ecosystems and conservation.
Conclusion: The correct answer is (D) W.G. Rosen.

Step 1: Understand dyslexia and its causes.
Dyslexia is a learning disorder that primarily affects reading and writing skills.
Environmental toxins such as lead have been implicated in causing neurological damage that may contribute to learning disabilities like dyslexia.
Step 2: Analyze the options.
Mercury, cadmium, and manganese are toxic metals, but lead is most commonly associated with neurological damage and developmental disorders, including dyslexia. Lead exposure, particularly in early childhood, is a known risk factor for learning disabilities.
Step 3: Conclusion.
The correct answer is (C) Lead, which is a significant cause of dyslexia.
The correct answer is (C) Lead.

Step 1: Understand the history of WHO.
The World Health Organization (WHO) was established on 7th April 1948 as the United Nations specialized agency for health, headquartered in Geneva, Switzerland.

Step 2: Analyze the options.
The WHO was established on 7th April, 1948, which corresponds to option (B). The other dates are incorrect.

Step 3: Conclusion.
The WHO was established on 7th April, 1948, making option (B) the correct answer.

Conclusion: The correct answer is (B) 7th April, 1948.