1.What do you call the number in front of a chemical formula that tells how many atoms or molecules of a substance take part in the reaction? A) yield

B) coefficient

C) symbol

D) subscript

2.A balanced equation has ?

A) the same number of reactants as products

B) the same total number of coefficients on both sides of the equation

C) the same number of each kind of atom on both sides of the equation

D) an equal number of molecules on both sides of the equation

3.In a chemical reaction, the total mass of the products .

A) must always be the same as the total mass of the reactants

B) is always less than the total mass of the reactants in an open system

C) can be greater or less than the total mass of the reactants

D) must be less than the total mass of the reactants

4.Due to the principle of conservation of mass, .

A) all chemical formulas have coefficients

B) all chemical reactions must have an equal number of reactants and products.

C) all chemical reactions must take place in open systems

D) all chemical equations must be balanced

help me please

The answer is d. areobic

Environmental science studies the interactions between the physical, chemical, and biological components of the environment, including their effects on all types of organisms. earth science (also known as geoscience), is an inclusive term for all sciences related to earth (geology, meteorology, oceanogr maphy, etc).  although environmental and earth science cover essentially the same material, environmental science places greater emphasis on the biological realm, while earth science places greater emphasis on the physical realm.    environmental and earth science study the interactions of four major systems or “spheres” (figure 8.6).  the  geosphere  consists of the core, mantle and crust of the earth.the  atmosphere  contains all of the earth’s air and is divided into troposphere, stratosphere, mesosphere, thermosphere and ionosphere.the  hydrosphere  contains all of the solid, liquid and gaseous water on earth, extending from the depths of the sea to the upper reaches of the troposphere where water is found.  ninety-seven percent of the hydrosphere is found in salty oceans, and the remainder is found as vapor or droplets in the atmosphere and as liquid in ground water, lakes, rivers, glaciers and snowfields.  the  biosphere  is the collection of all earth’s life forms, distributed in major life zones known as biomes:   tundra, boreal forest, temperate deciduous forest, temperate grassland, desert, savannah, tropical rainforest, chaparral, freshwater, and marine.although the four systems have their unique identities, there is substantial interaction between them.  environmental scientists study the effects of events in one sphere on the other spheres. for example, a volcanic eruption in the geosphere may cause profound direct and indirect effects on the hydrosphere, atmosphere and biosphere as follows: example 1 (volcano)    on may 18, 1980, mount saint helens, in the state of washington, erupted.  this event altered the surrounding environment, and provided scientists with an opportunity to study the effects of volcanic eruptions on the geosphere, hydrosphere, atmosphere and biosphere.  such studies are vital because volcanic eruptions will continue to occur, and will have increasing impact on humans as people continue to settle lands closer to dormant volcanoes. the following are but a few of the myriad of interactions resulting from a volcanic