How can you tell plant cells have thickness?

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

Ecosystems involve living organisms interacting with non-living things in a productive way; how is photosynthesis an example of this? answer, i will give brainiest to first person to get it right.

What type of appendages do sponges cnidarians roundworms annelids mollusks arthropods echinoderms and vertebrate have? jointed, not jointed, absent