Answer:
1. equality 
2. wealthy 
3. straighten 
4. exploit 
5. treasures 
6. toughest 
7. moisten 
8. streamline 
9. poisonous 
10. pedigree 
11. creatures 
12. ceiling 
13. volunteer 
14. shoulder 
15. guaranteed 
16. appointment 
17. earthbound 
18. impeach
Step-by-step explanation:
Synonyms are the words that mean somewhat or similar to the word. The words that are related to the main word, or provide an equivalent meaning to it are termed to be synonymous words. 
Synonyms helps in providing an elaborate meaning and gives a substitution of the word. 
In section A, synonyms are to be chosen and written for the given words. The synonymous words are to be selected from the given box. 
In section B, the words that helps in forming the complete sentence will be used.