
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Psychologists have found that there is a relationship between students' acceptance ability $y$ of concepts and the time $x$ (in minutes) spent proposing the concepts. $(0 \leqslant x \leqslant 20$, a larger value of $y$ indicates a stronger acceptance ability).

| Time spent proposing concepts $x$ (minutes) | 0 | 1 | 2 | 5 | 7 | 10 | 12 | 13 | 14 | 17 | 20 |
|--------------------------------------------|---|---|---|---|---|----|----|----|----|----|----|
| Acceptance ability $y$                     | 43| 45.5| 47.8| 53.5| 56.3| 59| 59.8| 59.9| 59.8| 58.3| 55|

Based on the information above, answer the following questions:
1. In the described changes in the table, what is the independent variable? What is the dependent variable?
2. When the time spent proposing concepts is 10 minutes, approximately what is the students' acceptance ability?
3. At what time spent proposing concepts do students have the strongest acceptance ability?
4. In what time range do students' acceptance ability gradually increase? In what time range do students' acceptance ability gradually decrease?

Present the answer in LaTex format: \boxed{Your answer}
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