Answers in order from top to bottom for statements on the left side of page.
1. Activate
2. Avoid
3. Integrate
4. Target
There is only one main element involved in the fusion reactions inside the sun; Hydrogen, but if you need a second element then it is more than likely that the question is asking for the isotope of hydrogen that is called <span>deuterium.
So basically, Hydrogen and Deuterium; an isotope of hydrogen</span>
The deep sea vent organisms or benthic organisms normally live in dark conditions because of no penetration of sunlight. These organisms in order to colonize ocean surface must develop photo sensory receptors and should adapt to the light conditions along with variation in temperatures and pressure in ocean currents.