This type of clothing should not be worn for parties, weddings and other formal or ceremonial events. They should not also be worn for work. Various items of clothing such as tee-shirts, denims, khakis, jackets, hoodies, mini-skirts, summer dresses, loafers, sneakers, and sandals are casual wear.
The presence of a lone pair decreases the bond angle between the bonding pair of electrons, due to their high electric charge which causes great repulsion between the electrons. They are also used in the formation of a dative bond.
(Think of a base pair as a single molecule.). In double-stranded DNA the base stacking interactions lock in the helix and the cumulative cooperative effect is enormous compared to the more flexible single strands.This is why DNA renaturation is enthalpically driven whereas protein folding is entropically driven.. The stability conferred by each hydrogen bond is the difference between the strength of the bond in double-stranded DNA and its strength in when bonded to water. Hydrogen bonds between bases and water molecules typically have strengths of about 25 kJ mol -1 and hydrogen bonds between base pairs are a bit higher.