Words such as ‘similar/different and problem/solution' students organize important information in textbooks.

An Antonym is a word opposite in meaning to another word, and this definition applies mainly adjectives although some other words such as: adverbs, verbs, and even abstract nouns also have antonyms.

Antonyms enrich our vocabulary providing multiple perspectives when communicating ideas.

Now, a synonym for the word Antonym is "contrasting" or "contrastive"  

Thereby, the above statement can be completed like this:  

"Contrasting/Contrastive words such as ‘similar/different and problem/solution' help students organize important information in textbooks."

yes

it is because 3 because the citizen the northern democratic party watned the warning on red to blue because it is purple. lol

muslims have taken his goods and products to different parts of asia an indonesia. sometimes just traveled and trade, but in other occasions, stayed in the place and made a living.

trade was the key for muslims economies to prosper. their commerce routes reached far places like malaysia and java in the 11th century.

another important factor for prosperity was that muslim states served as the middle point for european traders.

they used to travel by land but sailing the seas -the indian ocean- really increase the exportation of products.