ADAPTATION 适应，适应性的变化
Every plant and animal has features that help it to survive in its environment. These features are adaptations(每一种植物和动物都有一些特征或特质来帮助他们在自己的环境中存活下来。这些特征和特质就是适应性的变化。)
For example:比如:
Polar bears have a thick layer of fat to keep them warm and meerkats have dark pathces around their eyes to protect them against the glare of the sun.(北极星有一厚层的脂肪帮助它们保持温暖而海岛鼬有黑眼圈来帮助他们抵御太阳耀眼的光芒。)
VARIATION (差异性)
The children in your class are not identical(你班里的孩子不是一模一样的). They have different-coloured eyes and different-sized feet(他们有着不同颜色的眼睛和不同尺寸的脚丫). The difference between indviduals is called variation.(这些个体之间的不同性被称作差异性。)
Living things produce offspring of the same kind.as themselves.For example , cats give birth to cats and humans give birth to humans.(生物产生相同的后代，比如猫生出猫，人类生出人类。) However , offspring of the same parents show variation.(然而，相同父母的后代产生差异性)。They are not usually identical to each other or their parents.(他们通常与彼此或者和父母并不完全相同)。
Offspring: The plants or animals that are produced by their parent or parents.(后代是指由父母或单一父或母产生的植物或动物)
