Which Nobel Prize winning scientist first demonstrated the role of mosquitoes in transmitting malaria through experiments carried out in Secunderabad (now in Telangana, India)?

Introduction / Context:
This question tests knowledge of the history of medical science and public health, especially the discovery that malaria is transmitted by mosquitoes. It highlights the important role of experiments carried out in Secunderabad in India, where a key Nobel Prize winning scientist proved how malaria spreads. Understanding this breakthrough is useful for general knowledge as well as for examinations related to biology, medicine and public health history.

Given Data / Assumptions:

• The scientist in question is a Nobel Prize winner.
• His early and decisive experiments were carried out in Secunderabad, now in Telangana, India.
• The experiments were related to malaria and the role of mosquitoes in its transmission.

Concept / Approach:
To answer this, recall major contributions to the understanding of malaria. Sir Ronald Ross, a British physician in the Indian Medical Service, is famous for discovering that the malaria parasite is carried by certain species of mosquitoes. He did this work while posted in India, and Secunderabad is explicitly associated with his historic experiments. Other Nobel laureates mentioned in the options made outstanding contributions in different fields, but not in the specific context of malaria experiments in Secunderabad.

Step-by-Step Solution:
Step 1: Identify which listed scientist worked on malaria and served in India. Step 2: Recall that Ronald Ross studied malaria in India and dissected mosquitoes to track the parasite in their gut. Step 3: Note that his crucial observations on the development of the malaria parasite in mosquitoes were made while he was posted at Secunderabad. Step 4: Compare this with Robert Koch, whose main work was on tuberculosis and bacteriology in Europe. Step 5: Alexander Fleming discovered penicillin, an antibiotic, in his London laboratory, unrelated to malaria in India. Step 6: Hans Adolf Krebs is known for the citric acid cycle in cell metabolism, and Paul Ehrlich for work in immunology and chemotherapy, neither linked to malaria research in Secunderabad. Step 7: Therefore, the only scientist matching all parts of the description is Ronald Ross.

Verification / Alternative check:
Ronald Ross received the Nobel Prize in Physiology or Medicine in 1902 for his work on malaria. Standard histories of malaria control describe how he confirmed that the malaria parasite passes through the mosquito and can be transmitted to humans, and they explicitly mention his experiments in Secunderabad. No similar association exists for Koch, Fleming, Krebs or Ehrlich in connection with Secunderabad, which confirms the correctness of the choice.

Why Other Options Are Wrong:
Robert Koch is linked with tuberculosis, anthrax and general bacteriology, not with malaria experiments in Secunderabad. Alexander Fleming is famous for penicillin and antibiotic research in the United Kingdom, not for mosquito based malaria work in India. Hans Adolf Krebs discovered the Krebs cycle in biochemistry and did not carry out malaria studies in Secunderabad. Paul Ehrlich worked on immunology, staining techniques and early chemotherapy, again unconnected with this specific Indian research setting.

Common Pitfalls:
A frequent error is to pick a very famous name like Alexander Fleming simply because he is widely known, without checking whether his work fits the geographic and thematic clues in the question. Another pitfall is ignoring the mention of Secunderabad and focusing only on the fact that the scientist is a Nobel laureate. Reading the entire stem carefully and linking malaria, India and Secunderabad leads directly to Ronald Ross.

Final Answer:
The Nobel Prize winning scientist who first carried out decisive malaria experiments in Secunderabad is Ronald Ross.