Which two substances are among the four major types or organic compounds made by living things, The answer C,
would be carbon dioxide
Answer:
The α‑helix is held together by hydrogen bonds between the amide N−H and C=O groups.
Disulfide bonds stabilize secondary structure.
Explanation:
Proteins have primary, secondary, tertiary and quartinary structures.
The secondary structure of a protein is the regular, recurring sequence of amino acid in a polypeptide chain. Secondary structure of proteins give rise to the folding observed in the structure of a protein.
The major secondary structures of a protein are α-helices and β-structures.
Answer: Saturated
A solution that contains the maximum amount of solute that is soluble at a given temperature is said to be saturated.
Explanation:
A Saturated solution is one that contains as much (i.e maximum) solute as it can dissolve at that temperature in the presence of undissolved solute particles.
For instance: if a given volume of water can only dissolve a certain amount of salt in it at room temperature, then, more salt added will not dissolve.
Thus, making the solution saturated.
True that in the preindustrial era, settlements were more likely to be near sources of surface water than in the industrial era. The main reason being that during the preindustrial era people were dependent mostly on irrigation. For irrigation people were dependent on surface water. This was the main and basic reason.