Correct Option
The correct option is 1 and 3 only.
Explanation
Terrestrial plants require raw materials for photosynthesis and metabolic processes. While carbon is derived from atmospheric carbon dioxide, the majority of other essential nutrients and water are obtained from the soil through the root system.
Statement-wise Analysis
- Statement 1 is Correct: Water is absorbed from the soil by the roots. The root system, specifically root hairs, increases the surface area for absorption, allowing water to enter the plant via osmosis and be transported through the xylem.
- Statement 2 is Incorrect: Plants cannot absorb nitrogen exclusively in the form of atmospheric gas ($N_2$). Atmospheric nitrogen is inert and cannot be utilized directly by plants. Instead, nitrogen is absorbed from the soil in the form of inorganic nitrates ($NO_3^-$) and nitrites ($NO_2^-$), or as organic compounds derived from nitrogen fixation.
- Statement 3 is Correct: Phosphorus is an essential mineral nutrient found in the soil. It is dissolved in the soil solution and is absorbed by the roots along with water. Other minerals like magnesium, iron, and potassium follow a similar uptake pathway.
Key Takeaway: Plants absorb water and dissolved mineral nutrients (such as nitrogen and phosphorus) from the soil via roots. They lack the physiological mechanism to directly assimilate gaseous nitrogen from the atmosphere.