Sinusitis is an inflammation of the sinuses. It is often caused by bacterial (germ) infection. Sometimes, viruses and fungi (molds) cause it. People with weak immune systems are more likely to develop bacterial or fungal sinus infection. Some people with allergies can have allergic fungal sinus infection. Acute sinus infection lasts three to eight weeks. A sinus infection lasting longer than eight weeks is considered chronic.
Define Upper stage. Upper stage synonyms, Upper stage pronunciation, Upper stage translation, English dictionary definition of Upper stage. n. A rocket composed of two or more propulsion units that fire in succession. Also called step rocket . Noun 1. multistage rocket - a rocket having two or...
Complete metamorphosis has four stages: Egg, Larva, Pupa, and Adult. In each stage of complete metamorphosis, the animal looks different than at all other stages. This is different from incomplete metamorphosis where the early stages of development look like tiny versions of the adult. Butterflies are an example of an insect that goes through all the stages of complete metamorphosis. Complete metamorphosis begins with the insect hatching from an egg into a soft worm-like shape called a larva. Larvae have a very big appetite and can eat several times their own body weight every day.