19 an effective collision between reactant particles requires the particles to have the proper
(1) charge and mass
(2) charge and orientation
(3) energy and mass
(4) energy and orientation

Which answer lists the fundamental forces in order from strongest to weakest

The diagram shows the structures of horse and cat forelimbs. what does the diagram suggest about the evolutionary relationship between these two mammals? a. they have homologous structures, indicating a common ancestor. b. they have analogous structures, indicating a common ancestor. c. they have homologous structures, indicating that they do not have a common ancestor. d. they have analogous structures, indicating that they do not have a common ancestor.

As changes in energy levels of electrons increase, the frequencies of atomic line spectra they emit