多节
发表于 2025-3-25 03:54:40
Introduction,s and in doing so pass their hereditary material on to the next generation. While reproduction is biologically meaningless with respect to the individual, it is essential to the preservation of the species over many generations and can, therefore, be regarded as the most important concern of all liv
逢迎春日
发表于 2025-3-25 08:41:25
Comparative Anatomy of the Urogenital System,e production of hormones which have an important role in the regulation of reproduction. This last aspect will be dealt with in Chapter 5. The existence of separate sexes is the rule in vertebrates, as has already been mentioned. The gonads of the male are the testes, those of the female the ovaries
Antigen
发表于 2025-3-25 13:28:52
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过度
发表于 2025-3-25 19:33:46
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终点
发表于 2025-3-25 23:34:19
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epinephrine
发表于 2025-3-26 02:52:41
Reproductive Behaviour,nal whereas the environmental change may be biotic or abiotic. Behaviour is manifest as a pattern of movements which are made up of a series of muscle contractions co-ordinated in space and time. These activities range from a part of the body being moved once to a number of individual movements, whi
Fretful
发表于 2025-3-26 07:28:45
Care of the Young Within the Body: Submammalians,are fertilised or unfertilised when laid. In many cases the parent animals take care of their eggs to some extent and of their young after they have hatched out, these being aspects of parental care (see p. 223). However, in many species of Elasmobranchii, Teleostei, Amphibia and Reptilia various me
GAVEL
发表于 2025-3-26 08:55:26
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Graphite
发表于 2025-3-26 15:18:08
Care of the Young Outside the Body, of the offspring’s survival. In the overwhelming majority of cases this is a passive phenomenon, that is, the parent animal carries the young in or on its own body and sustains them in some way from its own metabolism but does not engage in any specific behavioural activity. In contrast to this, su
小口啜饮
发表于 2025-3-26 19:04:05
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