Question

1. Which joiner shows a contrast between coordinate ideas?

Answer 1

1. The correct answer is nevertheless.
Coordinate ideas are those that are equally important in a sentence - you cannot say that one is more important than the other. If you want to show contrast between them, you would choose the joiner nevertheless, which basically means however. 

2. The correct answer is therefore.
The joiner therefore shows us a particular result. So, something happened, and therefore something else happened as a result of the first event. Therefore means the same as consequently (which implies a consequence, or a result), as well as hence, thus, accordingly, etc.

Answer 2

The answers of the following are:
1. The joiner that shows a contrast between coordinate ideas is: Nevertheless = In other words, it also means "however".
2. The joiner that shows a result between coordinate ideas is: Therefore. In other words, it also means "as a result", or "consequently".