Items that have degraded heavily become unusable until they are repaired. The region has been badly degraded, mainly due to grazing. Ethidium bromide can be degraded chemically, or collected and incinerated. The remnant caldera rim has been degraded deeply by erosion. Most specimens have partially degraded before discovery, due to exposure or to being scavenged. Additionally, accuracy can be significantly degraded by jitter on the signal being measured. The O is rapidly degraded by the existing microbial populations. In the cytoplasm it may be degraded entirely or retained. It also proposes ways for restoring degraded landscapes. In mammals, norepinephrine is rapidly degraded to various metabolites. Pyridine is readily degraded by bacteria to ammonia and carbon dioxide. This cycle repeats until starch is degraded completely. It is ascertained that the grasslands of Ningxia have been degraded to various degrees. Tetrachloroethylene is degraded by hydrolysis, and is persistent under aerobic conditions. Gargan's previous identity has not been completely degraded.