Answer:
In the electromagnetic spectrum, the visible spectrum is the part, which is perceptible to the human eye. The electromagnetic spectrum in this array of wavelengths is known as simply light or the visible light. A general human eye will react towards the wavelengths in the range between 380 to 740 nm. A human eye sees the sky as blue that comes in the wavelength 490 nm because of the scattering of the visible light by the particles in the atmosphere. This concludes that 490 nm is the sole wavelength, which is reaching the eye.
CLOUD FORMATION, he said it under the question but i put it here so it would be easier too find
Answer:
Abiotic is basically a non living factor so the answer is
D. Sunlight, temperature , conductivity, dissolved oxygen.
All other options contain one biotic or living factor like algae, star fish and crabs these aren't Abiotic.