Elasticities of demand GapFill

In the short run, demand elasticity will be   elasticunitaryperfectly elastic inelastic and becomes more  inelasticunitaryperfectly elasticelastic in the long run. Necessities such as water, housing, etc. tend to have elasticity of demand that is  inelasticelasticunitaryperfectly elastic. In respect to price elasticity of demand (PED), the value of elasticity must always have a  negativehighpositivelow sign because of the inverse relationship between price and quantity on the demand curve. Normal goods and inferior goods must have  lowpositivenegativehigh and  positivehighnegativeelastic relationships respectively. Goods that are jointly demanded have  a positivea crossan incomea negative price elasticity of demand that is  unitarypositivenegativeperfectly elastic. When a change in price yields the same proportionate change in quantity demand then its PED will be  elasticunitaryzeroperfectly elastic.