principles of biology final exam Questions & Correct Answers/ Graded A+

Where do most organisms get their energy from either directly or indirectly? : sun What is a tissue? : any of the distinct types of material of which animals or plants are made, consisting of specialized cells and their products. What is an experimental variable? : something that a scientist changes during the course of an experiment. What is a community? : a group of people living in the same place or having a particular characteristic in common. what is an ion? : an atom or molecule with a net electric charge due to the loss or gain of one or more electrons. 2 About how much of the planet is covered by water? : 70 percent Which type of bond is the strongest? : covalent bond What is the octet rule? : States that atoms lose, gain or share electrons in order to acquire a full set of eight valence electrons Define element. : is composed of atoms that have the same atomic number, that is, each atom has the same number of protons in its nucleus as all other atoms of that element. Define matter. : physical substance in general, as distinct from mind and spirit; (in physics) that which occupies space and possesses rest mass, especially as distinct from energy. In reference to the period table, what is a period? : a horizontal row of elements in the periodic tabl