Growth and change
成长与变化
Plants usually reproduce through seeds and grow in stages.
植物通常通过种子繁殖，并分阶段生长。
First, a seed germinates and begins to grow.
首先，种子发芽并开始生长。
Roots come out of the seed.
根从种子里长出来。
Then, a stem grows up out of the ground.
然后，一根茎从地里长出来。
Next, the stem grows leaves.
接下来，茎长出叶子。
It now looks like its parents.
它现在看起来像它的父母。
As the plant grows and grows, it matures and becomes an adult plant.
随着植物的生长，它成熟并成为成年植物。
By contrast, animals reproduce in several ways.
相比之下，动物有几种繁殖方式。
Female mammals give birth to their young.
雌性哺乳动物产下幼崽。
The young look like their parents.
年轻人看起来像他们的父母。
The young grow and grow.
年轻人成长。
They mature and become an adult.
他们成熟并成为成年人。
Humans, cats and dogs are mammals.
人、猫和狗都是哺乳动物。
Frogs are amphibians.
青蛙是两栖动物。
Their young are called tadpoles.
它们的幼崽叫做蝌蚪。
They come out of an egg.
它们是从鸡蛋里出来的。
They have a tail but do not have legs.
它们有尾巴，但没有腿。
They look different from their parents.
他们看起来和父母不一样。
As they mature, they grow legs and the tail disappears.
当它们成熟时，它们长出腿，尾巴消失了。
As an adult, they look like their parents.
成年后，他们看起来像他们的父母。