The Rat

THE RAT Mammalia (Mammals) - Rat External cha pukeeristics The body is dissever into a head, neck, trunk and tail and is cover by hair. The rat has cardinal pairs of limbs. Each of the front legs has iv toes, from from each(prenominal) one nonpareil with a claw. Each of the posterior legs has five toes, each with a claw. On the head ar deuce ears with pinnae rescript to the front. At the front of the head below the ears are two eyes, each with a movable upper and lower chapeau and a nictitating membrane. At the tip of the pointed snout are two extenal nostrils precisely above the split upper lip of the mouth. On each side of the split upper lip are capacious sensitive whiskers. The long tongue acts as an reed reed organ of taste and helps with eating. Both the upper and lower jaws have teething situated in sockets. The neck is short and thick. On the adaxial surface of the females trunk there are six pairs of teats. The genital opening (vagina), anus and and urin ary opening are separate in the female and are found between the hinder(prenominal) legs. In the male the urinary and sexual opening open collectively at the tip of the penis. The scrotum holds the testes outside the body between the hind legs. The tail is long and ends in a thin point.

nurture During sex act the penis of the male is inserted into the vagina of the female. The sperms are dismissed and and fertilisation occurs internally in the oviducts. The zygote develops into the embryo in the uterus of the female. The placenta, an inner(a) physiological connection between the embryo and the mother, supplies nutrient and respiratory gases and removes ! wastes and carbon dioxide from the embryo. After a gestation accomplishment the new(a) are born... If you want to get a full essay, instal it on our website: BestEssayCheap.com

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