With reference to soil conservation, consider the following practices: 1. Crop rotation 2. Sand fences 3. Terracing 4. Wind breaks

(d) All are soil conservation methods.

(b) 1. Rotation of the Earth 2. Air pressure and wind 3. Density of ocean water. Revolution has no import on ocean current.

(d) Contour Bunding is one of the simple method of soil and water conservation. This technique is used at places where the land is sloppy. Due to slope, soil and...

(d) Crop rotation, Sand fences, terracing and wind breaks all are used for sand conservation in India. Sand fences is a simple and cheap method of inducing accretion of sands...

(d) Doldrums are noted for their calm periods when winds disappear totally. They are a low pressure area around the equator.

(d) Brown soil

(b) Phosphorous enters into the soil through water.

Kharif : Rice or Soyabean, Rabi : Pea or Wheat.  Pea/Soyabean are legumes that will fix nitrogen with the help of Rhizobium.