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Photomicrograph of section through rat testis, showing seminiferous tubules. ... 17802loa – Histology Learning System at Boston University; Image; Diagram Archived ...
A systematic detection and eradication system was used throughout a control zone about 600 kilometres (400 mi) long and 30 kilometres (20 mi) wide along the eastern border [further explanation needed] to eliminate rat infestations before the rats could spread further into the province. Shotguns, bulldozers, high explosives, poison gas, and ...
The brown rat (Rattus norvegicus), also known as the common rat, street rat, sewer rat, wharf rat, Hanover rat, Norway rat and Norwegian rat, is a widespread species of common rat. One of the largest muroids, it is a brown or grey rodent with a body length of up to 28 cm (11 in) long, and a tail slightly shorter than that. It weighs between 140 ...
Laboratory rats or lab rats are strains of the rat subspecies Rattus norvegicus domestica (Domestic Norwegian rat) which are bred and kept for scientific research. While less commonly used for research than laboratory mice , rats have served as an important animal model for research in psychology and biomedical science .
A sexual system is a distribution of male and female functions across organisms in a species. [1] [2] The terms reproductive system and mating system have also been used as synonyms. [3] Sexual systems play a key role in genetic variation and reproductive success, and may also have led to the origin or extinction of certain species. [4]
Kangaroo rats have a promiscuous mating system. Their reproductive output is highest in summer following high rainfalls. [18] During droughts and food shortages, only a few females will breed. [4] It appears that kangaroo rats can assess their local conditions and adjust their reproductive efforts accordingly. [18]
The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones , and pheromones are also important accessories to the reproductive system. [ 1 ]
The mammalian female reproductive system contains three main divisions: the vagina and uterus, which act as the receptacle for the sperm, the ovaries, which produce the female's ova, and the vulva, which consists of the labia and clitoris. The vagina, uterus and ovaries are always internal while the vulva is external.