Read the article on oxygen in the atmosphere. For questions 1-5, choose
the correct answers (A, B, C or D). Justify
your answers.
1 Air that is mainly oxygen is
A low in free radicals.
B useful to the body.
C dangerous to humans.
D bad for evolution.
2 Oxygen is
A 50% of the atmosphere.
B necessary in order for life to exist.
C the result of atmospheric chemistry.
Dunnecessary for plants.
3 According to the article, animals
A couldn't have evolved without plants.
B took a long time to get big in size.
C were anaerobic at first.
D needed large breathing systems in the past.​

wondermang    1   12.05.2021 07:13    34