Answer:
the food chain
Explanation:
every species in the ecosystem eats or gets eaten
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.
Answer: Nutrition
Explanation: Nutrients are the essential nourishments for growth and the maintenance of life.
Answer:
River basin is the area of land that is drained by a river system.
Explanation: River basin is also called drainage basin. River basin consist of one main big stream which collects water from many tributaries present on the left and right of the main stream. Water is collected from high ridge areas into these tributaries due to precipitation over there. These high areas is known as watershed. This main stream flows and drain into a river system.
