Avoiding Surcharges. Because airlines charge a peak travel day surcharge on the most popular days of travel -- Sunday, Monday and Friday -- you can get the best discounts on those off-peak days. However, during the summer, peak and off-peak travel days do not really exist.
Proteins are essential nutrients for the human body. They are one of the building blocks of body tissue, and can also serve as a fuel source. As a fuel, proteins contain 4 kcal per gram, just like carbohydrates and unlike lipids, which contain 9 kcal per gram.
Protein serves both structural and functional roles in the human body. Different types of protein are involved in building up the structure of the human body eg. Actin and myo â¦ sin (two proteins) make muscle cells, keratin makes hair, etc. Proteins serve structural roles by being a component of the cells. They serve functional roles by catalysing reactions in human body eg, enzymes (proteins) are involved in all the reactions that take place in human body eg, Kreb's cycle involves an array of enzymes to help cells utilize respirated oxygen in human body.