Some of the first organisms to show cephalization were octopuses jellyfish flatworms sponges

Every compound can be represented by a chemical formula. a chemical formula is the set of symbols showing the elements that make up a compound and their proportions. water’s chemical formula is h 2 2 o. that means a molecule of water contains two atoms of hydrogen and one atom of oxygen chemically bonded. a molecule is a group of two or more atoms bonded together. molecules can range in size from two to thousands of atoms. a molecule of a compound is the smallest unit of that compound. every molecule of water has all the physical and chemical properties of water. that’s because every molecule of water is made of the same elements in the same proportions: two hydrogen atoms and one oxygen! which of the following is a true statement? a every molecule of the same compound will have different properties. b every molecule of a compound has the same proportion of elements. c molecules can be physically separated into smaller units of a compound. d molecules cannot be represented by chemical formulae.

After fertilization, which type of cellular division is responsible for the growth and development of a complex, multicellular organism?

The circles, or orbits, for electrons are called energy levels. each level can hold only a certain number of electrons. add electrons to each level until you can't add any more. how many electrons can each level hold?