全班 65% 的同学考试成绩高于均值

全班 65% 的同学考试成绩高于中数

全班 65% 的同学考试成绩高于众数

全班同学考试成绩是负偏态分布

The sperm has to get through corona radiate to finish fertilization.

Fertilization occurs when the sperm can deliver its genetic material.

The egg is released from the fallopian tube to meet the sperm.

When egg and sperm fuse, a diploid cell is formed.

全班65%的同学考试成绩高于均值

全班65%的同学考试成绩高于中数

全班65%的同学考试成绩高于众数

全班同学考试成绩是负偏态分布

Menstruation

Bleeding

Ovulation

Menopause

正确

错误

全班 65%的同学考试成绩高于均值

全班 65%的同学考试成绩高于中数

全班 65%的同学考试成绩高于众数

全班同学考试成绩是负偏态分布

Menstruation

Bleeding

Ovulation

menopause

. 【甲】 文通过乙钓鱼效率的提高 ， 突出了甲所说道理的正确性 ， 也表明乙极不情愿听取别人意见 ， 对甲的话不闻不问 。

. 【甲】 文写出了做事不能急躁 ， 要淡定从容 ， 专心致志 ， 持之以恒 ， 保有内心的宁静 ，才 能取得好的成绩

. 【乙】 对于羊子拾金 ， 其妻引用古训劝丈夫不要求利污行 ， 阐述了做人要洁身自好的道理 ； 对于羊子辍学 ， 其妻以织布为喻劝丈夫不要中途弃学 ， 阐明了学习要持之以恒的道理 。

. 【甲 】【乙】 两文在写法、构思上都有相同之处 ， 都有情节 ， 有人物 ， 有议论 ， 有描述 ， 以小见大 ， 寓意发人深省 。

Of the 300 million human sperm ejaculated during ual intercourse, only about 200 reach the site of fertilization in the oviduct. Sperm are attracted to an ovulated egg by chemical signals released by both the egg and the supporting cells that surround it. Once a sperm finds the egg, it must migrate through a protective layer of cells and then bind to, and tunnel through, the egg coat, called the zona pellucida.

Finally, the sperm must bind to and fuse with the underlying egg plasma membrane. Although fertilization normally occurs by this process of sperm–egg fusion, it can also be achieved artificially by injecting the sperm directly into the egg cytoplasm; this is often done in infertility clinics when there is a problem with natural sperm–egg fusion.

Although many sperm may bind to an egg, only one normally fuses with the egg plasma membrane and introduces its DNA into the egg cytoplasm. The control of this step is especially important because it ensures that the fertilized egg—also called a zygote—will contain two, and only two, sets of chromosomes. Several mechanisms pr multiple sperm from entering an egg. In one mechanism, the first successful sperm triggers the release of a wave of Ca 2+ ions in the egg cytoplasm. This flood of Ca 2+ in turn triggers the secretion of enzymes that cause a “hardening” of the zona pellucida, which prs “runner up” sperm from penetrating the egg. The Ca 2+ wave also helps trigger the development of the egg. To watch a fertilization-induced calcium wave.

The process of fertilization is not complete, however, until the two haploid nuclei (called pronuclei) come together and combine their chromosomes into a single diploid nucleus. Soon after the pronuclei fuse, the diploid cell begins to divide, forming a ball of cells that—through repeated rounds of cell division and differentiation—will give rise to an embryo and, ually, an organism. Fertilization marks the beginning of one of the most remarkable phenomena in all of biology—the process by which a single-celled zygote initiates the developmental program that directs the formation of a new individual.