Question

Assertion: Maximum contribution of oxygen is from phytoplankton.
Reason: 50% of the photosynthesis with oxygen evaluation is contributed by them.
A) Both Assertion and Reason are correct and reason is the correct explanation for Assertion.
B) Both Assertion and Reason are correct but reason is not the correct explanation for Assertion.
C) Assertion is correct but reason is incorrect.
D) Both Assertion and reason are correct.

Answer 1

Hint: The ecosystem in a body of water is called the aquatic ecosystem. Aquatic ecosystems are commonly categorized based on moving or still and based one is fresh, saline, and brackish. An aquatic ecosystem aquatic video I, two major types is based on salinity- the marine ecosystem and, the freshwater ecosystem. Martin’s ecosystem and the firewater ecosystem. The marine ecosystem covers 70% of the earth’s surface. The Marine ecosystem is the largest. The freshwater ecosystem covers 2% of the earth’s surface.

Complete answer:
A) Assertion and Reason are correct and the reason is the correct explanation for Assertion: The illuminated upper 200 to 300 meters of the open ocean, termed the phonetic zone, is home to a diverse collection of microbes. Phytoplankton is the source of all organic matter in the open ocean with exception of the hydrothermal vents. Roughly half the carbon fixation in the open ocean is performed by cyanobacteria in the genera Rhodococcus and Synechococcus. These microbes help constitute the phytoplankton, which represents 20% -80% of the total phytoplankton biomass. Larger unicellular cyanobacteria and eukaryotes the autotrophs especially biomass. minute floating plants called phytoplankton and are widely distributed through the lake photosynthesis penetrates.

B) Assertion and Reason are correct but the reason is an incorrect explanation for Assertion: A maximum of oxygen is contributed from phytoplankton because 50% of the photosynthesis can be attributed to the evaluation of oxygen. So the reason is also the correct explanation for the assertion. This option is wrong.

Hence, the correct answer is option (A).

Note: Lakes are divided into phonetic and aphotic on basis of light penetration. The phonetic zone is the uppermost layer of the lake. Where there is no or little sunlight. The portion of a lake where it is little or no sunlight penetrates is called the aphotic zone. It is formally defined as the depth below 1% light penetrates. Hence photosynthesis is a photosynthetic organism decline with depth as a function of declining available light, whereas respiration is relatively constant with depth. The depth at which photosynthesis is equal to respiration is called the compensation depth.