Listen to part of a lecture in a biology class.
There are certain animals that live high in the mountains, at altitudes of above the tree line, where trees don't grow. And moving around in this mountainous environment can be challenging. Because the mountain slopes can be very steep and rocky. Besides that there's often ice or snow making these rocky slopes slippery and dangerous. So animals that live at high altitudes have special features that help them move around in this difficult mountainous environment. So for one thing, many mountain animals have strong muscles that help them climb up and down the steep slopes. As they moving around looking for food, they have to climb up these really steep mountain sides at a dramatic incline and get down again too. For many animals this will be a real problem requiring great strength and balance. Mountain goats, which live high up in the mountains in parts of North America, mountain goats have a very well-muscled chest and front leg area, and these big developed muscles in this area help them pull themselves up these near-vertical slopes and balance in type positions when climbing down. Also, mountain animals often have specially adapted feet that help them keep from slipping when they are walking over ice or rocks. High altitude mountain slopes can be very slippery, especially when there was snow or ice on them. And it's a long way down if they fall. So mountain animals need to have a safe, sure footing. Take the big horn sheep for instance. These sheep have special toes that move independently so they can dig into the rock and ice. And the back parts of their feet have special round rubbery pads that help them grip the surface of the rock or ice, to prevent sliding as they move around.
Using the examples of the mountain goat and bighorn sheep, explain two special features that help animals move around in a mountainous environment.
名师1对1，深度分析薄弱项，高效提分
In the lecture, the professor introduces two features which help animals move around in a mountainous environment. The first feature is they have strong muscles which can help them climb up and down. For example, the mountain goats have big muscles which enable them to move up and down on steep reefs. The second feature is about their safe footing. The professor talks about a kind of sheep whose toes can move independently to dig into rock or ice. Also these toes can be used to grip the surface of rock and ice in order to make the animals move in the mountainous area.
