1,if we put the highest mountain in the world into (If we pu

1,if we put the highest mountain in the world into (If we put the highest
mountain in the world into the deepest parts of the sea,___. A. we can still see the sea water),
2,划线的them指的是plants?；
3,Under the sea,the deeper ,the colder是正确的吗?根据这个文章
The sea looks very beautiful when the sun is shining on it. But it can be very terrible when there is a
strong wind. The sea is very big. It covers three quarters of the earth. The sea is also very deep in some
places. In one place, the sea is about 11 kilometres deep. The highest mountain(山) in the world is about
nine kilornetres high. If that mountain was put into the sea at that place, there would still be two
kilometres of water above it!
In most parts of the sea,there are plenty of f ishes and plants (植物). Some live near the top of the
sea.Others live deep down. There are also a lot of small living things, and lots of fish live by eating __them__.
The sea can be very cold. When people go down, the sea becomes colder and colder. Only some men
can go down into the deep sea. But, in 1970, five women scientists lived in the deep sea for fourteen
days.