When someone is "assertive," he or she is very confident. This can come off as being arrogant because such a person can be a little pushy, but the primary meaning of assertiveness is the character trait of being confident. Therefore, the best option is simply "confident." Do not be tricked by "conceited" or "arrogant". These are trap options!

When someone is "attentive," he or she is very aware of his or her surroundings. Therefore, "attentive" can mean merely to be very aware. None of the options exactly match this meaning, but a secondary meaning of "attentive" is "to be thoughtfully aware of others." This is clearly related to the first meaning, though it is a little more focused. Therefore, the best option is "thoughtful," as this expresses at least the second meaning of "attentive."

The word "responsible" can mean guilty, as when we say, "He was responsible for the crime." Someone can also be "responsible for himself or herself." Whenever we grow up, we become more "responsible," meaning that people can rely on us to do what we say we are going to do. An immature person is not yet responsible. A mature person is. Hence, "mature" is good synonym for "responsible." This has nothing to do with age. It has everything to do with a good character. You're only young once, but you can immature forever!

Whenever someone is "meek" he or she has a very kind and quiet personality. This kind of person can be afraid to assert himself or herself. A decent synonym for "meek" is "humble." A humble person is someone who does not think too highly of himself or herself.

Whenever someone is "assertive," he or she could be described as being pushy. The verb "assert" means to declare or to insist. An "assertive" person is usually pretty confident. This can seem "arrogant," but he or she might just be very certain of himself or herself. Thus, the best option among those given is "confident".

When someone is "distracted," he or she does not have his or her attention on whatever is happening at that very moment. The word "preoccupied" describes someone who has his or her attention totally absorbed by something. For instance, you might become preoccupied with working on a project. When you are preoccupied in this way, you are distracted from everything else and cannot pay attention to anything else.

Whenever someone is "jovial," he or she has a happy temperament. Often, the word "jovial" can be used to describe someone who is both happy and friendly. Therefore, among the options provided here, the word "sociable" is fine. A person who is jovial company is very sociable and gets along with people in a group.

"Boisterous" means very active and noisy in a lively way, therefore the best word with the closest meaning would be "rowdy."

Maybe you have heard of "toxic waste" or "toxic chemicals." The word "toxic" describes something that is not healthy but, instead, is poisonous. This is not the same as being "murderous," but it is the same as being "deadly." "Deadly" things are dangerous and harmful—as are toxic ones. "Toxins" are things that are harmful (or toxic) in this way.

Whenever two things are distinct, they are different from each other and cannot be confused with each other.  For example, we could say, "Those two character traits are distinct.  Some people can be angry without turning red."  This means that turning red is something different than being angry.  The best option among those provided is "separate", for this communicates the idea of being two distinct realities.