When did the level of oxygen in earth's atmosphere become high enough to sustain aerobic respiration? when did the level of oxygen in earth's atmosphere become high enough to sustain aerobic respiration? 3.5 billion years ago 1.5 billion years ago 2.7 billion years ago 1.0 billion years ago

Which other elements contain the same number of outer electrons as sodium

Identify one disadvantage to each of the following models of electron configuration: -dot structures -arrow and line diagrams -written electron configurations type in your answer below. (answer) -dot structures do not show the distribution of electrons in orbitals and take up a lot of space. -arrow and line diagrams take up a lot of space and make it difficult to count electrons. -written configurations make it easy to lose count of electrons and do not show the distribution of electrons in orbitals.

In apex! a liquid heated beyond a certain temperature becomes