[jiang]

Dear teachers,

I have four questions to ask:

No.1
Please read the following sentence:

Destructive insects often undergo a "flare-back", in numbers greater than before.

Here number is in plaural form. May I sum up the use of number this way?

a. a great number of students: many students
b. students in ( great ) numbers: many students
c. 20 students in number: 20 students

No.2
Nature holds the species within bounds. Can I replace 'bounds' with 'limit'?
One importatn natural check is a limit on the amound of suitable habitat for each species. Can I replace 'limit' with 'bound'?

No.3
I got confused by 'importation' and 'import' when both of them mean 'something that is brought into a country in this way'. In other words, can I replace 'import' in the expression 'cheap imports of grain' with 'importation'?

No.4
'adapt' can mean 'to gradually change your behaviour and attitudes so taht your get used to a new situation and can deal with it successfully. 'adjust' can also mean 'to gradually get used to a new situation by making small changes to the way you do things'. Does it mean when used in this meaning they are interchangeable? For example, can I use 'adapting' to replace 'adjusting' in the sentence?
Adjusting to the tropical heat was more difficult than they had expected.

Looking forward to hearing from you.

Thank you in advance.

Jiang