Duckweed performs photosynthesis. Photosynthesis produces oxygen. They take in carbon dioxide and produce oxygen. So, when it is kept in the light cycle it will produce oxygen which will get dissolved in the water.
But the flask with water does not contain dissolved oxygen. So, at the end of light cycle the flask containing the plant will have more DO.
Now, in dark the plant does not produce oxygen. Instead it uses it to break the glucose and produce carbon dioxide. While this is not the case with the flask without the weed.
So, the flask without the plant will have more DO then the flask with the plant.
So, at the end of light cycle the flask with the weed will have more oxygen while at the end of dark cycle the flask with water will have more DO.
Octopus and squid have little suction cups on their tentacles. It helps with sticking onto food (so it doesn't get away) and also helps with sticking into things. If it wanted to camouflage into some rocks, it can use its tentacles to cling to to the rock.
Tentacles can also grab and carry things. Scientists have made tests where they would put a clam in a jar with the lid screwed on. The octopus would grab onto the jar and use its tentacles to twist the lid off.
Without tentacles, octopuses and squids would be pretty helpless and probably couldn't survive in the deep ocean.
Answer:
D. Any or all of the above could be causing the problem.
Explanation:
Pollution has been said to have adverse effect on living organisms. In this question, a decrease in number of intertidal organisms has been observed. Since a major freeway runs along a stretch of the ocean shore, the most likely cause of the death of the intertidal organisms is the release of any form of toxic waste into the water body.
Oil pollutants causes death of living organisms by hindering the entrance of oxygen into the water body. It makes it difficult for oxygen, which is a requirement for life, to penetrate the water body. Hence, living organisms in the water body will suffocate and die.
Toxic wastes also causes the death of organisms when ingested in excess. Waste water causes deterioration in the oxygen content of the water body. Hence, any or all of the above options can likely cause the reduction in number of the intertidal organisms.
A C - only male expressed the disorder and only females carried the disease. This is typical of a special type of diseases where only females are and can be carriers and only men can and are affected. There aren't many diseases like this but they do exist.
