Since the 1970s, the production of packaging and disposable products has increased significantly, as has the production of waste, especially in developed countries. Today, many governments and NGOs are charging companies with responsible stances: economic growth must be combined with preservation of the environment.
Reproduction is sexual, with species often (oligoquet and hirudinous) hermaphroditic and with direct development. There are, however, forms with separate sexes and indirect development, through a trochaphous larva and some cases of asexual reproduction (polychaetes). Fertilization is always external.
Reproduction of coelenterates can be asexual or sexual. In many species there is alternation of sexual and asexual phases. Asexual reproduction usually occurs by budding. In this case, shoots are formed in certain regions of the animal's body; each bud develops and gives rise to a new individual.
The planet inside and out The soil you step on; the rocks that shape the mountains; the bottom of rivers, lakes and seas: all this is just a thin "shell" of the immense planet that is Earth. The Earth The earth is roughly spherical in shape and flattened at the poles. Its internal structure is divided into earth's crust, mantle and core.
Noise pollution in large cities has long been the subject of many discussions about its detrimental effects on human health. More recently, the United Nations (UN) has reported its concern about increasing noise pollution at sea as well. Apparently, this pollution is affecting and endangering the survival of marine species.
Insects have identified heroin and cocaine odors; Researchers suggest that animals could be used at airports. Bees could replace sniffer dogs at airports, researchers suggested Researchers at the University of Cologne in Germany say they have trained bees to identify heroin and cocaine odors.