Use the periodic table to determine how many atoms of phosphorus (p) are in a sample that has a mass of 172. 90 g.

Afood web shows who eats who in any given habitat. every living thing, from one-celled algae to giant blue whales, needs food to survive. each food web is a possible pathway that energy and matter can follow through the habitat. a food web begins with producers: organisms that convert sunlight into usable chemical energy. the food web is completed by the decomposers who turn organic wastes, such as decaying plants, into inorganic materials, such as nutrient-rich soil. decomposers complete the cycle of life, returning nutrients to the soil or oceans for use by producers. in this food web, identify the decomposer.

If (a, b) is the solution to the system of equations shown above, and a and b are integers, then what is the value of a+b?

By what percent will the product of two numbers change, if the first number increases by 70%, while the second number decreases by 40%.