The answer is
1) Valves between atria and ventricles close, 2) first heart sound heard, 3) valves between ventricles and body close, 4) second heart sound heard
Answer:
-Abiotic factors such as light, water, and temperature
-The more light, the faster the plant is able to photosynthesize, however, plants reach its level of maximum photosynthesis if the intensity of light is too high
-Temperatures above or below range of 0 degrees Celsius and 35 degrees C can cause damage to enzymes, ceasing photosynthesis
-If too much or too little water is applied, plant cells may wither and die, or explode
Explanation:
The cell has to use active transport when it's trying to transport material against the concentration gradient. (from low to high concentration) Or, if a molecule is too big to diffuse through the cell membrane, it must be moved through using a carrier protein.
Hope that helped you.