研究发现纯合紫粒玉米的花粉完全败育，不具备受精能力，其它类型玉米的花粉正常．将杂合白粒玉米和纯合紫粒玉米进行间行种植，F₁中收获得到的玉米共有三种类型：白粒、黄粒和紫粒．回答下列问题：

生生死死的水草，在季节的轮回中起起落落，却不曾泯灭绿色的梦想。

    She was a student at a secondary school. The school was across the street from my house. Every day， I w____ her play basketball after school from my house. She played very well，b____ than any one of her classmate. And she never stopped. She practised over and over again， sometimes u____ dark.

    One day， I asked her， “Why do you practise so hard? You are playing very well.”

    “That's b____．I want to play in the city basketball team，” She looked d____ into my eyes and said. “But I'm still not good enough. I must work hard.” I was moved by her great c____.

     Another day， I saw her crying on the grass，i____ of playing basketball. I walked across the street and sat down by her side.

    “Why are you crying， girl?” I asked.

    “The c____ of the city basketball team told me I couldn't go on playing basketball because I was too short.”

     But some days later I saw her playing basketball again， practising e____ harder than before. I was curious and asked her the reason.

    “My father told me if my d____is big enough， nothing can stop me.”

    I was moved again.

马一直以来是一种高贵优雅的动物,是力与美的象征,被人们称为行走在地上的龙。请你自拟题目,写一篇和马相关的习作,注意理清写作顺序,不少于400字。