Which of the following must happen first if natural selection is going to take place? 1. variation in organisms 2. selective advantage of one trait over another 3. reproduction 4. time 5. generic mutation

When in solution, a molecule that moves slowly across an artificial membrane moves rapidly across a plasma membrane. this molecule rapidly enters the cell regardless of whether its concentration is higher inside or outside the cell. using this information, which transport mechanism is most likely to be responsible for the movement of the molecule across a plasma membrane? view available hint(s)when in solution, a molecule that moves slowly across an artificial membrane moves rapidly across a plasma membrane. this molecule rapidly enters the cell regardless of whether its concentration is higher inside or outside the cell. using this information, which transport mechanism is most likely to be responsible for the movement of the molecule across a plasma membrane? active transportexocytosis

Which of the following particles always has a positive charge? a. electronb. neutron c. proton d. ion

During convection, less dense fluid rises and denser fluid sinks.