Final answer:
Semantic categorization activities, where students sort words into meaning groups, are effective for expanding vocabulary and enhancing decoding skills, ultimately building a better mental dictionary.
Step-by-step explanation:
The activities in which students must decide if words belong in the same meaning category are known as b. Semantic categorization. This method is productive for building a mental dictionary and reinforcing decoding skills. It involves sorting words into groups based on their meanings, as explained by the principle of semantic encoding, which shows that people tend to remember words in categories, hence paying attention to the meanings of the words as they learned them. This process not only aids vocabulary acquisition but also enhances the ability to understand and remember words.