Conjunctions are the words that are used to combine two or more than two words, groups of words or sentences.
- She and her siblings study in the same school.
- His Drawing is excellent but his Mathematics is poor.
- We can reach the island by ship or helicopter.
- Too much of money can spoil our habits whereas poverty can make us starve.
- Henry has not worked at all, therefore, he will not get a single penny.
The highlighted words in the above sentences (and, but, or, whereas, and therefore) perform the function of combining. Therefore, they are Conjunctions.