Algae （水藻） are very simple plants.They grow in fresh water or salty water.Seaweed （海藻） is algae that grow in salty water.Seaweed is red or brown in color.The Japanese people use these plants from the sea in many ways.From it,they make a food called Kombu.Kombu is seaweed that has been dried,cooked and pressed together.Then it is dried again and cut into long pieces.The Japanese eat a lot of Kombu and like it very much.
Japanese farmers often use seaweed as fertilizer （肥料）.It makes their plants grow better.Many farmers also find seaweed makes a fine food for their animals.
From seaweed the Japanese also get iodine （碘）,which they sell to other countries.Iodine is used in many ways all over the world.It is used in making medicine.It is added to the salt we use at the table.Scientists even use one form of iodine to "seed clouds" when they want rain to fall.

（1）Kombu is a kind of ______ according to the text.
A.plant
B.food
C.medicine
D.fertilizer
（2）In the last sentence of the text, "seed clouds" means ______.
A.clouds spreading like seeds
B.dropping seeds by clouds
C.the seeds like clouds
D.to make rain fall with human power
（3）Which is the main idea of the story? ______
A.The Japanese eat seaweed when they want rain to fall.
B.Kombu is made into medicine for farmers.
C.The Japanese use seaweed in many ways.
D.The Japanese eat a lot of Kombu.