Proteins are built from different amino acids

(c) polymers; 20

Explanation:

surface modification is a versatile tool and has been widely used in material science and engineering that has significantly facilitated the study and characterization of complex materials. at  matexcel, experienced experts in surface science can offer tailored efforts to meet the specific needs from our clients.

answer: national resource conservation services

national resource conservation services is the us. based approach that provides technical and financial assistance for natural resource management. nrcs society in conservation of resources by involving in activities like farmland protection, flood prevention, watershed protection, urban conservation, conserves economic and environmental conditions. it conducts soil surveys and implements the policy of natural resources management on the society.