The prefix "acri-" means related to bitterness or harshness. The word “acrid” means unpleasantly sharp or bitter in smell or taste. To provide further help, “soothing” means comforting; “pacifying” means calming; “jaunty” means cheerful; “cantankerous” means grumpy. 

The Latin root "duct" means to lead. You may, for example, have seen an "aqueduct," which literally "leads water" in a particular direction. Someone or something that is "ductile" is "able to be led," in the sense of being easily influenced or bendable. This is also the meaning of the word "pliant." "Rigid" is an antonym.

The prefix "ocu-" refers to being able to see, or to the eyes. This is similar to the prefix "vis-," which means to see. We can infer that “ocular” and “visual” are closely related to one another. To provide further help, “audio” means having to do with sound and hearing; “tactile” means able to be touched; “condemned” means considered guilty and awaiting punishment.

The prefix "ten-" means able to be held or defended, so the word “tenable” describes an idea that is able to be held or defended. We could also call this a “reasonable” idea. To provide further help, “debunk” means disprove; “catastrophic” means disastrous; “ambiguous” means unclear; “sporadic” means random and occurring infrequently.

The word "placid" means calm and peaceful. For example, one might write, "You could see your reflection like a mirror image in the placid lake." So, "calm" is the correct answer.

The prefix "agr-" means having to do with farming or the land, as seen in the word “agriculture.” The word “agrarian” means having to do with to the land or agriculture, so "of land" is the correct answer.

"Hospitable" means generous and friendly in entertaining guests, so "neighborly" would be the best match, as both words mean friendly.

"Hospitable" means receiving guests warmly and generously. The best choice is "friendly" because it means showing kindness and helpfulness. Someone who receives guests warmly and generously would be acting in a friendly manner toward those guests. 

The word "benevolent" means kind and caring. The best choice is "compassionate" because it shares the same definition. Considering the other choices, "violent" means acting with uncontrolled, rough force, "loud" means great in volume, and "ruckus" means noisy commotion.

The root "fid" refers to belief, so someone who is “diffident” is lacking self-belief. Of the five answer choices, this is most similar in meaning to “hesitant,” which means uncertain and not confident. To provide further help, “reckless” means careless, quick to get into danger; “hasty” means rushed; “swift” means very quick; and “thoughtless” means carless, inconsiderate.