Hello, to answer your question. It is because all machines require a fuel or source to power it making it imperfect for using some source that may not be renewable.
Signed by, Virtouso Sargedog
Answer: Chosen landforms are:
1) Hill
2) Mountain
3) Plateau
4) Valley
Explanation:
1) Hill is an elevated location smaller than a mountain. Location: Land
2) Mountain is a large mass of earth and rock, rising above the common level of the earth or adjacent land, usually given by geographers as above 1000 feet in height (or 304.8 metres).
Location: Land or Water
3) Plateau is a largely level expanse of land at a high elevation. It is also known as tableland.
Location: Land
4) Valley is an elongated depression between hills or mountains, often with a river flowing through it.
Location: Land or Water
Mass of X₂O₇ = 54,9g
2x + 33,6g = 54,9g
2x = 54,9g - 33,6g
2x = 21,3g | :2
x = 10,65g/mol
