A.I. Explanation:

Option 1: "applied-art objects"

Explanation: The word 'they' in the passage refers to 'applied-art objects' as it is mentioned in the context of how these objects follow basic patterns determined by the laws of physics. The sentence structure indicates that 'they' is used to describe the subject of the previous clause, which is 'applied-art objects.' This aligns with the overall theme of the text, which discusses the characteristics and limitations of these objects.

Option 2: "the laws of physics"

Explanation: This option is incorrect because 'the laws of physics' is not the subject being described by 'they.' Instead, the laws are the determining factors for the forms of applied-art objects, not the objects themselves. Therefore, 'they' cannot refer to something that is not the main subject of the preceding sentences.

Option 3: "containers"

Explanation: This option is incorrect as 'containers' is mentioned in a different context. The text discusses pots and their inability to function as containers if they lack bottoms or have large openings. Thus, 'they' does not refer to 'containers' but rather to the applied-art objects that are being analyzed.

Option 4: "the sides of pots"

Explanation: This option is incorrect because 'the sides of pots' is a specific part of the pots being discussed, not the subject of the sentence where 'they' appears. The text does not suggest that 'the sides of pots' are being described in the same way as 'applied-art objects,' making this option irrelevant.