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,
List of 11 Important Phylum | Animal Kingdom. 1  1. Phylum Protozoa (Approximately 30,000 Known Species): 2  2. Phyllum-Porifera (Approximately 5000 Known Species): 3  3. Phylum Cnidaria (Approximately 10,000 Known Species): 4  4. Phylum Ctenophora (Approximately 80 Species): 5  5. Phylum Platyhelminthes (Approximately 6500 Known Species): Flat-worms, Flukes and Tape-worms. These are flat, un-segmented, worm-like creatures with soft and bilaterally symmetrical body. In a bilaterally symmetrical animal there is a right side and a left side, a fore end and a hind end, a dorsal or back surface and a ventral or front surface.