4 Turbellarians are monoecious with the reproductive systems adapted for internal fertilization. And the monogenetic flukes (class Monogenea) are mostly ectoparasites of fishes.
涡虫是雌雄同体的，生殖系统适于体内受精。单起源的吸虫（单殖纲）大多是鱼的外寄生虫。
| 单词 | Internal fertilization |
| 释义 |
Internal fertilization
英语例句库
4 Turbellarians are monoecious with the reproductive systems adapted for internal fertilization. And the monogenetic flukes (class Monogenea) are mostly ectoparasites of fishes. 涡虫是雌雄同体的，生殖系统适于体内受精。单起源的吸虫（单殖纲）大多是鱼的外寄生虫。
英语百科
Internal fertilizationInternal fertilization is the union of an egg cell with a sperm during sexual reproduction inside the body of a parent. For this to happen there needs to be a method for the male to introduce the sperm into the female's reproductive tract. In mammals, reptiles, some birds, some fish and certain other groups of animals, this is done by copulation, the penis or other intromittent organ being introduced into the vagina or cloaca. In most birds, the cloacal kiss is used, the two animals pressing their cloacas together while transferring sperm. Salamanders, spiders, some insects and some molluscs undertake internal fertilization by transferring a spermatophore, a bundle of sperm, from the male to the female. Following fertilization, the embryos are laid as eggs in oviparous organisms, or in viviparous organisms, continue to develop inside the reproductive tract of the mother to be born later as live young. |
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