Amino acids are organic compounds and building blocks of proteins. Twenty standard amino acids find their involvement in human biology, but the question seems to seek any three specific examples. Thus, the task should consider alanine, cysteine, and glutamine. Alanine (Ala) is a non-polar aliphatic amino acid that is usually found in the alpha-helices and beta-sheets of protein structures owing to its small size and flexibility. Cysteine (Cys) is unlike the others because of the presence of a sulfur atom, which can establish disulfide bonds with one another, assisting in the structural stability of the protein. Glutamine (Gln) is a polar, uncharged amino acid that contains amide, and is important in metabolism, especially maintaining nitrogen balance in the body and being a substrate for rapidly dividing cells such as immune cells. Each of these amino acids serves myriad functions during various biological processes, thus illustrating the spectrum and importance that amino acids represent in life.

Hardness varies depending on the type and grade of metal. Hardness is determined by the material's ability to resist dents and scratches. Steel. especially hardened and alloyed steel. usually has a higher hardness rating than pure titanium. Titanium. however. has a stronger-to-weight ratio than steel. meaning it is lighter stronger and less dense than steel.

The world's largest producers of titanium are Australia. South Africa. Canada. South Africa. India. Mozambique. Norway. Ukraine. and Sierra Leone.