Correct Option
The correct option is (a) 1 only.
Explanation
Resources are generally classified based on their exhaustibility into renewable and non-renewable resources. The term "Stock of Resource" broadly refers to the total quantity of materials in the environment that have the potential to satisfy human needs. While technical definitions sometimes distinguish "Stock" (potential but no technology) from "Reserves" (accessible with technology), in a general context, stock refers to the aggregate volume of a resource available in nature.
Statement-wise Analysis
- Statement 1 is Correct: In the context of this question, the "stock of resource" is defined as the amount of resources available for use (or potentially available in the environment). It represents the total inventory at a specific point in time.
- Statement 2 is Incorrect: Renewable resources are those which can be reproduced or renewed by physical, chemical, or mechanical processes (e.g., solar energy, forests, water). However, their stock is not always unlimited. While some resources like solar and wind are inexhaustible (flow resources), others like water, forests, and soil can be depleted if the rate of consumption exceeds the rate of replenishment.
- Statement 3 is Incorrect: Non-renewable resources (e.g., minerals, fossil fuels) occur over very long geological times. Their total stock in the Earth's crust is finite and limited. Once consumed, they cannot be replenished within a human lifespan.
Key Takeaway
Non-renewable resources have a fixed, finite stock. Renewable resources are replenishable, but their immediate availability (stock) can be limited and subject to depletion if overutilized (e.g., groundwater).