Why are there males and females? Why are there two sexes instead of three, or twelve, or one? On this Moment of Science we'll learn why two is the magic number. Let's start with why there is sex at all. When two organisms reproduce sexually, sperm an

发表于:2018-12-27 / 阅读(39) / 评论(0) 分类 英语听力广播—Listening

Egg Cells 卵细胞 Do you know what an egg cell is? 你知道什么是卵细胞吗? An egg cell is necessary for reproduction. 卵细胞是繁殖的必要条件。 Animals have egg cells. 动物有卵细胞。 Then does every animal have egg cells

发表于:2019-01-10 / 阅读(51) / 评论(0) 分类 与美国小学生一起学英文第10册

近日,《科学》杂志在线报道称,剑桥大学的科学家们通过使用两种干细胞以及一个三维支架,成功地创造出了一个能够自行组装的结构,其发育和构造非常接近自然的小鼠胚胎。科学家的研

发表于:2019-02-01 / 阅读(16) / 评论(0) 分类 阅读空间

WASHINGTON, Aug. 4 (Xinhua) -- Researchers have found a way to turn mouse embryonic stem cells into sperm and this finding opens up new avenues for infertility research and treatment, according to astudy published Thursday in the online edition of jo

发表于:2019-02-04 / 阅读(117) / 评论(0) 分类 英语新闻

Scientists say early experiments suggest it may one day be possible to make babies without using eggs. 科学家称,早期实验表明,将来某一天或许不需要卵子就能孕育出婴儿。 They have succeeded in creating healthy baby mice

发表于:2019-02-17 / 阅读(25) / 评论(0) 分类 阅读空间

Nor did the procedure fulfil any unmet medical need. 此程序也未能满足任何未知医疗需求。 For the child whose genome was edited to confer resistance, the claimed benefit is protection from a virus that she may never encounter 对于为产

发表于:2019-02-25 / 阅读(40) / 评论(0) 分类 经济学人综合