Could someone explain what a 'thallus' is?

Invasive species are one of the major threats to biodiversity. these species multiply quickly and compete with native species for food, sunlight, spac and other resources. on the map, determine the area where native species will have limited resources available to them due to invasion threat from invasive species threat very low low medium high very high

Environmental differences within ecosystems are generally caused by

Aboy jumps into a cold swimming pool and his body tempature goes down hus muscles ,blood vessels