Selectively permeable (or semi permeable) means where for example a membrane can choose what material can pass through while others cannot. They control the in and out of materials.
This is because the membrane has tiny spaces, where only smaller molecules can pass through, other larger ones cannot.
Answer:
D. It absorbs photons from the sun and gives energy to electrons.
Answer:
The two strands of the parent DNA are separated, and two daughter DNA strands are formed.
Explanation:
DNA replication is a complex process which replicates or produces new DNA molecule from the parent DNA molecule mediated by enzymes and ATP.
The mechanism of DNA replication is known as the semi-conservative mode in which one new strand of DNA is synthesized complementary to the one strand of DNA. To form a new DNA molecule both the strand of the DNA gets separated and then a new daughter strand is formed complementary to each parent strand.
Thus, the selected option is correct.
Answer:
The atmosphere is the largest reservoir of the nitrogen as it is composed of 78% of Nitrogen. Although 78%, this is not used by the organisms directly as the nitrogen molecule exists in nature in the form of divalent joined via triple bonds.
These triple bonds require a great amount of energy to be broken and used. Only a few prokaryotic organisms called nitrogen-fixing bacteria have the capability to break these triple bonds as they contain enzymes-nitrogenase complex which converts the atmospheric nitrogen to usable forms like ammonia, nitrates and nitrites. About 92% of the atmospheric nitrogen is fixed through this way rest through thunderstorms and Haber's process.
Thus, nitrogen-fixing bacteria is the answer.
