Reef-building corals were
confined to relatively shallow depths because
many of these corals have microscopic algae
called zooxanthellae living inside their soft tissues.
These algae
are often important for the corals’ nutrition and
growth, but require sunlight for photosynthesis. There is no sunlight deep in the water.
In addition the oxygen in the Earth's atmosphere absorbs wavelengths at the edge of the ultra-violet region of the spectrum. The resulting color, which appears like a pale blue, actually is a mixture of all the scattered colors, mainly blue and green.
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Humans get energy indirectly from the sun, but directly through plants. plants get energy from the sun through photosynthesis, and we eat the plants.
A. Interphase.
The cell makes a copy of DNA during the S-phase which is in the interphase. An easy way to remember this is by realizing that the S stands for synthesis and DNA Synthesis is what it is called.
