плиз помогите!!!нужно вставить предлоги где это необходимо!!!

1) People have always studied living things in their natural environment.
2) How does our environment influence on our children?
3) I don't think people living in isolation could be happy.
4) Ecologists study what happens to different species of birds and animals.
5) What size shoes do you wear?
6) What are the relations between the two families?
7) Young people often send e-mails to each other.
8) Mr Brown is 92 years old but he is in good health.
9) What's the number of children in your family?
10) Nowadays people often travel by air.

1) in
3) in
4) with
5) of
6) between
7) to
8) in
9) of
10) by

В примере 2 предлог не нужен.

People have always studied living things in their natural environment.
How does our environment influence on our children?
I don't think people living in isolation could be happy.
Ecologists study what happens to different species of birds and animals.
What size shoes do you wear?
What are the relations between the two families?
Young people often send e-mails to each other.
Mr Brown is 92 years old but he is in good health.
What's the number of children in your family?
Nowadays people often travel by air.

1) in
2) -
3) in
4) to
5) -
6) between
7) to
8) in
9) of
10) by

1) People have always studied living things ...their natural enj ronment. 2) How, does our environment influence our children? 3) I don't think people living .IN isolation could be happy 4) Ecologists study what happens AT different species of birds and animals. 5) What size OF shoes do you wear? 6) What are the relations BETWEEN the two families? 7) Young people often send e-mails TO each other. 8) Mr Brown is 92 years old but he is IN good health. 9) What's the number OF children in your family? 10) Nowadays people often travel BYair.

а варианты ответов есть?
из того, что могу точно назвать:
2.on
7.to
а вообще, половина предложений довольно странная.
если понадобится помощь, пишите в личку.