Which of the following are essential factors that need to be considered to decide when and how much a cultivated field needs to be irrigated? P. the crop to be sowed.
Q. the number of weeds in the field.
R. the nature of the soil S. the average amount of rainfall the region receives.
T. the type of tractors used in the field.
1 only P, R and S
2 only P. Q and R
3 only P. Q and S
4 All - P. Q. R, S and

the correct answer is 2 and 4

1. amino acid refers to the fundamental building block of proteins, comprising of an amino group and a carboxyl group.

2. catalyst refers to any substance, which increases the rate of chemical reaction without being used up in the reaction.

3. a complex molecule containing he genetic code is dna or deoxyribonucleic acid.

4. an enzyme refers to a molecule of protein, which is unique in accelerating up a particular chemical reaction in the biological systems.

5. nucleic acid refers to an sequence of sugars, phosphates, and nitrogenous bases, for example, dna and rna.

6. a protein refers to a large, composite organic molecule comprising of a huge number of amino acids associated together with the of peptide bonds.

7. rna refers to a nucleic acid that takes part in the production of proteins.

8. substrate refers to a compound, which takes part in a chemical reaction, and is chemically modified by the reaction.