4b) visual observations as the sample is brought near the side of the flame, in the flame, and out of the flame, 4c) odor as the fibres burn, 4d) characteristics of the ash including the colour and texture. 4e) The man-made fibers will decompose and melt. much quicker than either the animal or vegetable fibers.
Bluefin tuna swim in a holding pen in Australia. A conservation group has named three fish species that it says are at risk of extinction. The fish are threatened because of overfishing to meet the worldâs growing demand for food.
Most fish that can only tolerate narrow ranges of salinity and are highly sensitive to any changes in the levels of salt to the water in which they dwell. These fish are known as stenohaline species and include goldfish, which can live only in a freshwater environment. Reversely, tuna can exist exclusively in saltwater, according to the NMFS.