The question is asking to identify the true statements from the given options. The problem states that Daniil bought 20 fish, and each fish is longer than 3 cm but not exceeding 7 cm. Let's analyze each statement: 1) Five fish in this aquarium are longer than 3 cm. This statement is plausible. Since all 20 fish are longer than 3 cm, any subset of these fish, including five, would also be longer than 3 cm. 2) There is a fish in the aquarium that is 2 cm long. This statement is false. The problem explicitly states that every fish is longer than 3 cm. 3) The difference in length between any two fish is not more than 5 cm. This statement might be true or false. The fish lengths are between 3 cm (exclusive) and 7 cm (inclusive). The maximum possible difference would occur if one fish was just over 3 cm and another was exactly 7 cm. In this case, the difference would be approximately 7 - 3 = 4 cm. If the smallest fish was, for example, 3.1 cm and the largest was 7 cm, the difference would be 3.9 cm. If the smallest fish was 3 cm (if that was allowed, but it says 'longer than 3cm') and the largest was 7cm, the difference would be 4cm. If we consider the range to be (3, 7], the maximum difference is 7 - (just above 3), which is less than 4 cm. The statement says 'not more than 5 cm', which is true because the maximum difference is less than 4 cm. 4) There is a fish in the aquarium that is 5 cm long. This statement is plausible. The lengths are between 3 cm and 7 cm. A fish of 5 cm falls within this range.