U.S. Greenhouse Gas Emissions. In the United States, greenhouse gas emissions caused by human activities increased by 7 percent from 1990 to 2014. Since 2005, however, total U.S. greenhouse gas emissions have decreased by 7 percent. Carbon dioxide accounts for most of the nationâs emissions and most of the increase since 1990. Electricity generation is the largest source of greenhouse gas emissions in the United States, followed by transportation.
The phylum Arthropoda (jointed foot) has the largest number of species. In fact, about 85 percent of known species are arthropods, and insects alone make up about 75 percent of known species. Other arthropods include the centipedes and millipedes; the arachnids (spiders, scorpions, ticks, mites); and the crustaceans (barnacles, crabs, crayfish, lobsters, shrimp, water fleas). Obviously,
A phylum is the taxonomical rank below kingdom and above class. The kingdom Animalia contains approximately 40 phyla. Organisms are grouped into phyla based on a general body â¦ plan. For example, the phylum Chordata contains all those animals with a spinal cord. The phylum Arthropoda contains all those animals who are spineless and have an exoskeleton. The level of classification between kingdom and class.