Final answer:
The characteristics of Third Declension Adjectives with two Nominative Singular Forms is 1) They have two Nominative Singular forms, one for masculine/feminine and one for neuter.
Step-by-step explanation:
Third declension adjectives with two nominative singular forms have two forms, one for masculine/feminine and one for neuter. In Latin, adjectives must agree with the gender and number of the noun they modify. For example, the adjective 'fortis' has two nominative singular forms: 'fortis' for masculine/feminine and 'forte' for neuter. So, if you have a masculine noun, you would use 'fortis,' and if you have a neuter noun, you would use 'forte'.
This characteristic of third declension adjectives allows for more precise agreement with the nouns they modify. Therefore third declension adjectives with two nominative singular forms have two forms, one for masculine/feminine and one for neuter. The correct answer is 1) They have two Nominative Singular forms, one for masculine/feminine and one for neuter.