问题
选择题
以下描述表示生物性状的是（ ）
①番茄果皮的颜色 ②豌豆豆荚的形状 ③人的ABO血型 ④鱼游泳的距离．
A．①
B．①②
C．①②③
D．①②③④
答案
生物体的形态结构、生理特性和行为方式都称为性状．如耳垂、皮肤的色泽、是单眼皮还是双眼皮，这些属于形态特征；人的血型、植物见光后叶绿体产生叶绿素，这些属于生理特性；大雁南飞属于动物的行为方式．因此①番茄果皮的颜色、②豌豆豆荚的形状、③人的ABO血型；④鱼游泳的距离与时间有关不是性状，鱼游泳时的姿势是性状．
故选C．
e are faced with a challenge, we usually have two __24__: we can try to beat it off, or we can decide that the thing presenting the challenge isn’t worth the _25__ and call it quits. Although there are _26_ times when calling it quits is
the right thing to do, in most cases all that is needed is commitment and _27_. 
ard as it was, it made me who I am today. And that is a good thing.” 