Questions

Since, the sentence starts talking about the reason; R will be the continuing statement as it goes with the flow of the statement. The continuing statement talks about the existing of life i.e. P. Thus, all other options are eliminated. The correct formation would be, ‘There is no reason why we should not be willing to think that life may exist in great profusion in other worlds.’

Genes : The DNA is the genetic material. The DNA is made of several nucleotides. A nucleotide means, one nitrogenous base one sugar molecule and a phosphate molecule. These nucleotides occur in sequences and several nucleotides form one Gene ( a functional mgene is called a cistron)

A deliverable is a measurable, verifiable work product such as a specification, feasibility study report, detailed design document, or working prototype.

Geysers are fountains of hot water and superheated steam that erupts with an explosion whereas hotsprings or thermal springs are found where water sinks deep enough the surface to be heated up by the interior forces and it comes out without any explosion. Iceland and New Zealand are the other countries having geysers while hot springs are relatively common.

ADP stand for Army Doctrine Publication.  An official written document that provides established principles in the U.S. Army that support national objectives.