What are 4 examples of physical changes?

This line graph compares the growth of plants that were kept in the sun for different amounts of time.a)  on day 7, the plants kept in the sun for 3 hours were how tall? b)  on day 7, the plants kept in the sun for 6 hours were how tall? c)    on day 10, the plants kept in the sun for 9 hours were how tall? d)  on day 11, the plant that was grown with 1 hour of sunlight was how tall? e)  based on the graph, the plant grows best in what amount of sunlight?

Ahydrogen atom has 1 electron. how many bonds can hydrogen form? a) 1 b) 2 c) 3 d) 4 e) 5

How to calculate the mass of copper