Answer:
C) period
Explanation:
Groups are columns on the periodic table (with the same number of electrons on the outer shell of the elements), whereas periods are rows (increasing in atomic number by 1 - 5, 6, 7, 8, 9 etc.)
Answer:
1 one is solar system I think so
Answer:
They are released into a river, lake, or ocean.
Explanation:
Organisms are the biotic parts of an ecosystem.