The e. coli that normally live in the human large intestines and produce vitamin k that the body uses would be best termed a relationship.

There are choices for this question namely:

A. parasitic 
B. saprobic 
C. commensal 
D. mutualistic 
E. None of the choices are correct.

The correct answer is mutualistic. This kind of relationship is a "give-and-take" relationship between the organisms wherein both organisms benefit from each other. In this case, the human gives the E. coli its habitat along with its food and nutrients. The E. coli on the other hand gives the human its normal gastrointestinal flora as well as providing vitamin K to ensure clotting mechanisms are intact.

Nimbostratus is the correct answer.
explanation: nimbostratus clouds are the type of clouds that are mostly likely present on gray, rainy day. these clouds produce continuous rain, snow and there is no thundering or lightening either.