The height could have been 35cm, the same as that of plants exposed to 12 and 14 hours of light. The optimum number of hours to this species of plant to grow is 12 hours. Therefore, the succeeding hours beyond this point does not contribute to the photosynthesis process.

The plant with the least number of hours exposed to light filed to grow in height because of the very short time of photosynthesis. Photosynthesis is the conversion of light energy to chemical energy that is stored in glucose or other organic compounds. There was less food produced in order for the plant to grow taller.

Correct Answer: (2) This type of bacterium would grow well at pH 7.5.

Based on the graph, the optimum pH for the growth of this bacterium is 8. From the choices, the nearest pH to 8 is 7.5.

Incorrect Answers:

Not all species of bacteria grow well at the same pH level. For instance, there are acidophilic bacteria which subsist in areas with pH 2.

Correct Answer: (2) A hypothesis may lead to further investigation even if it is disproved by the experiment.

A hypothesis is an explanation for a question or a problem that can be formally tested by experimentation. The results of the experiment will help the scientist draw a conclusion abut whether or not the hypothesis is correct. In case that the hypothesis is incorrect, another hypothesis can be formed which is subject for further study.

Correct Answer: (4) not enough information is given to determine whether the organism is a plant or an animal

Most plants are green, but an animal like a frog (e.g. Rana clamitans) is also green. Aside from that, a single-celled chlorophyte like Phacus is also green in color. Therefore, color is not sufficient information to conclude the type of organism.

Correct Answer: (2) The red blood cells will lose water and decrease in size.

Osmosis is the diffusion of water across a selectively permeable membrane depending in the concentration of the solutes on either side of the membrane. The water moves from an area on low solute concentration to an area with high solute concentration. In the case of the red blood cells, since it has lower salt concentration, the water will move out of the cell and thus the cell will decrease in size.

Correct Answer: (1)

Pulse rate is the rate of the heart beat. It is measured by the number of beats per minute. Pulse rate is affected by the activities of muscles of the body. The more vigorous the movement, the more blood is needed to supply oxygen and energy to the muscles, and thus, the faster the pulse rate. Among the four activities performed by the student, watching TV (A) required the least movement by the body. It is followed by talking while sitting down (D), then walking going to his friend's house (B). The most vigorous activity he did was running to the mall (C), and therefore the highest pulse rate was recorded.