Answer:
Aquatic ecosystems include oceans, lakes, rivers, streams, estuaries, and wetlands. Within these aquatic ecosystems are living things that depend on the water for survival, such as fish, plants, and microorganisms. These ecosystems are very fragile and can be easily disturbed by pollution.
Explanation:
The right answer is C. I think, a. and d. are obviously not serious. B is not true, because Ag and Au are in the same group in the periodic table and therefore have the same number of electrons in the last level. So, they form ions with the same charge. C is true beacause Ag and Au have different numbers in the periodic table and different amount of protons and neutrons in their nucleuses.
By pushing on the top of it and the water or substance will get into it
#5 is Anemia
#6 is Deficiency
and thats all i know from the top of my head