Why are there always more members on the lower trophic levels than the higher trophic levels?
as energy moves from one trophic level to the next, more and more energy is available for the next level limiting the number on the next level.
the members of the lower trophic levels are always small in size so there can be more of them.
as energy moves from one trophic level to the next, less and less energy is available for the next level limiting the number on the next level.
the members of the lower trophic levels pass on all of their energy to the next trophic level.

Elements and compounds are pure substances that cannot be broken down physically into a simpler substance. a physical change doesn’t break the bonds between atoms of a substance or form new ones. compounds can be broken down by a chemical change. a chemical change breaks chemical bonds and/or forms new ones between atoms of a substance. what simple substance would a compound break into? the basic elements that make it up! for example, if you passed a very strong electric current through water you’d break the chemical bonds in water and be left with oxygen and hydrogen. which of the following is an example of a chemical change? a separating water into different glasses b breaking frozen ice cubes with a hammer c running an electric current through water d boiling water to evaporate it on a stove

The oxidizing agent our bodies use to obtain energy from food is oxygen (from the air). if you breathe 15 times a minute (at rest), taking in and exhaling 0.5 l of air with each breath, what volume of air do you breathe each day? air is 21% oxygen by volume. what volume of oxygen do you breathe each day?

Describe how a student should adjust the microscope to see the cells on a slide more clearly?