Harry 發問於 社會及文化語言 · 9 年前

要Free Writing!10點!一天時間!

Free Writing,80字就得架啦!

不要和http://hk.knowledge.yahoo.com/question/question?qi... 文章內容一樣就行

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  • 9 年前
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    In biology, sex is a process of combining and mixing genetic traits, often resulting in the specialization of organisms into a male or female variety (each known as a sex). Sexual reproduction involves combining specialized cells (gametes) to form offspring that inherit traits from both parents. Gametes can be identical in form and function (known as isogametes), but in many cases an asymmetry has evolved such that two sex-specific types of gametes (heterogametes) exist: male gametes are small, motile, and optimized to transport their genetic information over a distance, while female gametes are large, non-motile and contain the nutrients necessary for the early development of the young organism.

    An organism's sex is defined by the gametes it produces: males produce male gametes (spermatozoa, or sperm) while females produce female gametes (ova, or egg cells); individual organisms which produce both male and female gametes are termed hermaphroditic. Frequently, physical differences are associated with the different sexes of an organism; these sexual dimorphisms can reflect the different reproductive pressures the sexes experience.

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