The heat of fusion is defined as the energy required at a constant temperature to change 1 unit mass of a 1. gas to a liquid 2. gas to a solid 3. solid to a gas 4. solid to a liquid​

space exploration has led to the development and technological improvement of many everyday items. (if this answer is wrong i will find the right answer) : )

answer; 4 electrons;

0.88m hope i am correct : )

the answer is symmetrical : )