Based on the above passage, the following assumptions have been made : 1. Giant icebergs have a bearing on primary productivity and food chains of the Southern Ocean. 2. Melting of giant icebergs can produce climate change effects and impact world fisheries. Which of the assumptions given above is/are valid?

1. A. 1 only
2. B. 2 only
3. C. Both 1 and 2
4. D. Neither 1 nor 2

Answer: A

Explanation

The passage states that melting icebergs release nutrients that support ‘unexpectedly high levels of phytoplankton growth.’ Phytoplankton are fundamental primary producers in marine ecosystems, forming the base of the food chain. Therefore, it is a valid assumption (Assumption 1) that giant icebergs influence primary productivity and, consequently, the food chains of the Southern Ocean. Assumption 2 is too broad and extends beyond the information provided. While changes in primary productivity *could* have wider implications for climate change and world fisheries, the passage does not explicitly establish these connections or generalize the impact from the Southern Ocean to ‘world fisheries.’ The question tests the ability to make logical inferences strictly based on the provided text.