Suggest why the plants in the Space Station are grown in enclosed containers

1. Suggest why the plants in the Space Station are grown in enclosed containers. *
2. Suggest why water has to be pumped directly to the plant roots, rather than just poured into the container from a watering can. *
3a. Explain why the roots of a plant grow in all directions if there is no gravity. *
3b. Describe how this problem has been solved in the Space Station. *
4. Explain why a sandy soil would not be a good choice for growing plants in the Space Station. (Use what you know about soils, and also the information above.) *
5. Describe three reasons why it would be useful for astronauts travelling on a long journey to grow plants in their spaceship. 


----- Nội dung dịch tự động từ ảnh -----
The International Space Station has been orbiting the Earth since the year
2000. More than 200 astronauts, from many different countries, have worked
on the Space Station.
Some of the astronauts carry out experiments to investigate how plants grow
in space. The plants are grown in small, enclosed, transparent containers.
They are given artificial light. Air and water are pumped around their roots.
The experiments show that, when there is no gravity at all, the plant roots and
shoots grow randomly in all directions. So some of the plants are spun gently
in a machine called a centrifuge. This produces a force to which the plants
respond just as they would respond to gravity.
One experiment has tested how the plants grow in different kinds of soils. If a
soil has very large particles, the water in it escapes easily. The water forms little
droplets and floats away into the air. If the particles in the soil are very small,
then air does not flow through it easily and the roots don't get enough oxygen
to survive.
The plants grown in the Space Station include dwarf wheat, strawberries and
mizuna. If humans ever travel to Mars, they will need plants to provide them
with oxygen and food. The experiments also show that the astronauts enjoy
growing the plants.