The best answer would be the first statement. The first sentence which is 'water pollution causes a decrease in fish populations in a river.' illustrates how human <span>activities can most directly change the dynamic equilibrium of an ecosystem.</span>
Carbs; fruits and vegetables, maybe grains and lentils.
Polar<span> molecules
water molecules have a weak, partial negative charge at one region of the molecule (the oxygen atom in water) and a partial positive charge elsewhere (the </span>hydrogen<span> atoms in water).The force of attraction is called a </span>hydrogen bond<span>.</span>
If they test more than one variable, they wouldn't know if it was both variables or one variable that was responsible for any observed effect.
The correct answer is "wildlife sanctuary"
These sanctuaries are places that emulate conditions met in natural habitats that are long gone and thus the animals that live in them have a place to live freely and survive.
