How to tell if a german noun is masculine or feminine?

What suffix would u fond in the word indicate related to

All of the following contribute to effective communication in groups excepta.)critical thinking. b.)understanding of subject matter. c.)individualism. d.)interpersonal communication skills.

Which type of context clue would define the word chary in the sentence below? matt excitedly jumped into his dad's new pickup truck, while his mother was chary about getting in. a. synonym b. antonym c. cause and effect d. explanation [ plz me im a retared ]