Cell wall for higher growth rates in diatoms. In brown algae, phlorotannins may be a constituent of the cell walls. The group Oomycetes, also known as water molds, are saprotrophic plant pathogens like fungi. Until recently they were widely believed to be fungi, but structural and molecular evidence has led to their reclassification as heterokonts, related to autotrophic brown algae and diatoms. Unlike fungi, oomycetes typically possess cell walls of cellulose and glucans rather than chitin, although some genera (such as "Achlya" and "Saprolegnia") do have chitin in their walls. The fraction of cellulose in the walls is no more than 4
History of the petroleum industry Arabia due to its crude reserves derived from bitumen. History of the petroleum industry The petroleum industry is not of recent origin, but petroleum's current status as the key component of politics, society, and technology has its roots in the early 20th century. The invention of the internal combustion engine was the major influence in the rise in the importance of petroleum. According to Herodotus, more than four thousand years ago natural asphalt was employed in the construction of the walls and towers of Babylon, great quantities of it were found on the banks of the river Issus, one of