Space Travel

Read about some space animals.Fill in the blanks with the correct words.
1.electrodes 2.orbit 3.monument 4.harness 5.artificial 6.weightlessness
7.sacrifice 8.outer space 9.spacesuit 10.cabins 11.ozone layers

The 1.___ of the lives of animals enabled humans to know more about the conditions in 2.___ beyond this planet's protective 3.___,for example,the effects of 4.___ on living things as well as the effects of stress on behaviour.The observations of animals in space.In the 1950's,nine space dogs were trained by the former Soviet Union yo test 5.___ in the pressured 6.___ of spaceflight capsules.
In 1957,scientists in the former Soviet Union sent the word's second 7.___ space satellite into space.A Russian dog named Laika was the frist animal to go into 8.___ with a life-support system.She was supported with a 9.___ that enabled her to move and have access to water and food. 10.___ were used to transmit her hearbeat,blood pressure and breathing rate back to Earth.Unforunately,the batteries operating her life-support system ran down only a few days into the flight and Laika died.
Forty tears later,a 11.___ can still be seen in Russia in honour of this flight and the subsequent sacrifice of other animals.