When someone is "affectionate," he or she is very caring and loving toward other people. Now, while such a person might also tend to be helpful, joyful, or even bubbly, these meanings are not strict synonyms for "affectionate." Affection is, above all else, about love. Thus, the best synonym among those provided for "affectionate" is "caring." (The word "caring" means more than "helpful"—it indicates an emotional attachment. This makes it a better option.)

The word "glee" means a great amount of happiness. Thus, a gleeful person is very happy. We could say, "The baby was utterly gleeful while playing with the small dog, giggling and slapping playfully at the ground." The main thing that you want to express with the word "gleeful" is happiness.  (Often, this happiness comes with great energy too; however, gleefulness is about happiness.)  Thus, the best option is "joyful."

The word "depressed" is used to describe someone who is very unhappy. When a person is "miserable," he or she is not happy or is very negative about life. Among the options given, this is the only one that closely matches "depressed".

"Furious" is an adjective meaning extremely angry. The only answer choice with a similar meaning is "enraged," which means very angry. The other words do not have similar meanings: "gruff" can mean no-nonsense or abrupt; "superb" means excellent; and "annoyed" means only slightly angry.

When someone behaves "erratically" they are acting in a way that is not expected, usual, nor even predictable. Therefore, "unpredictable" would be the word closest to this meaning and is a synonym for erratic.

“Fragile” means easy to break or "breakable." As for the other answer choices, “robust” means sturdy and strong; “stern” means enforcing the rules or strict; “firm” means strong or hard and not easily forced into a different shape; “logical” means rational or not breaking any of the rules of formal logic.

The word "firm" is an adjective used to describe something that is physically solid. For example, a firm pillow is one that is somewhat hard—as opposed to a very soft pillow. Sometimes, too, this word is used to describe someone's actions. For example, to say, "He was firm about his wish to have at least eight hours of sleep," means that the person did not give up his desire for the sleep (even if others protested).

The word "compact" comes from root words meaning joined together. When we compact our garbage, we compress it into a small space. When we describe the garbage as being "compact," we are indicating that it is very densely packed together. "Dense" things do not have much air space. The same is true for compact materials.

If something is colossal, it means that it is massive or immense. For example, a mistake can be colossal if it is large.

"Immense" is an adjective that means "extremely large or great, especially in scale or degree." So, we need to pick out an answer choice that means something like "very big." That means that "puny" can't be the correct answer, because "puny" means "small and weak" or "poor in quality, amount, or size," so "puny" is an antonym of "immense." "Gargantuan," however, is an adjective that means "enormous," so "gargantuan" is the correct answer because it is the answer choice closest in meaning to "immense."