Your answer would be A. Phosphorus
Basically, there is a presentation of types of food and the amount of those foods over 50 years in this graph. This means the graph is showing amounts of certain foods over the time period. I'm guessing that basing off of the the previous text you're just noting a change in the breaks of birds based off of the diet available to them at certain times. The adaptations and natural selection will explain the changes because due to certain limited and available foods the diet of the birds change.
Answer:
Disulfide linkage/bond
Explanation:
The tertiary and quarternary structure of the protein is stabilized by Disulfide linkage which is formed between two thiol groups in the protein. 2-mercaptoethanol is a reducing agent that breaks this disulfide bond.
A protein becomes denature when it loses its native configuration and becomes inactive. So as 2-mercaptoethanol breaks disulfide bond in protein it looses its native configuration and becomes denatured. 2-mercaptoethanol is used in SDS-PAGE to separate protein subunits. Therefore the correct answer is Disulfide linkage/bond.
