Which of the following is a problem caused by dams? O A. They can be used to generate electricity.
B. They provide water for the irrigation of crops.
.
O C. They impede fish migration and spawning.
O D. They collect and store water for human use.

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

plants need sunlight, water, and carbon dioxide to make food. plants use the raw materials of water, nutrients they absorb from soil, and carbon dioxide to make sugars the plant can use. energy from the sun and chlorophyll are also needed.