A series of vertical steps in a stream made to avoid soil scouring is called ________?

The unit of a scale used to measure the level of acidity or alkalinity of chemicals is called:

The experimental design which control fertility variation in one direction is known as________?

Insects belong to class________?

Which of the following techniques is/are used for the soil fertility evaluation?

The emigration of highly skilled and educated professionals and technical man power from developing to developed countries?