Enzymes are biological catalysts. Catalysts lower the activation energy for reactions. The lower the activation energy for a reaction, the faster the rate. Thus enzymes speed up reactions by lowering activation energy.
        
             
        
        
        
<span> The answer is <span>centriole</span>
The majority of cells have mitochondrion as they need them for their respiration. Chloroplast is the structure plants use to produce their organic matter, the vacuole is very developed in plant cells and is central where as you usually have many vacuoles in animal cells, and the centriole is usually present in animal cells only as well as the wall of cellulose that wraps up the plant cell.</span>
        
             
        
        
        
Answer:
C
Explanation:
The gravity of the sun and moon pull on the water of the oceans of the earth hence causing a bulge of these waters at the point on earth where the moon is above. The region where the moon is above, and the opposite side on the earth, will therefore experience high tides while the places at right angles (on the surface of the earth in relation to the moon position) will experience low tides. 
 
        
             
        
        
        
<h2>The work of Charles Darwin and Alfred Wallace </h2>
Explanation:
C) uniform modification of genetic traits over long periods of time. 
The theory of uniformitarianism  states that the natural phenomena and laws that are bringing about changes in the today's world are functioning in the same rate since the geological times. This idea of uniformitarianism was linked to biological sciences because according to Darwin and Wallace's observation, the uniform modification of genes among the population brought about the species diversity on the Earth.