Use appropriate sentence connectors in the blank spaces of the following passagE-

Scientists have always wondered (a) _____ there is life anywhere out in the spacE- They have joined together in a major project called the communication with Extra Terrestrial Intelligence (b) _____ seeks to establish contact with any other living beings in the universE- (c)_____ they are beaming out radio signals into the spacE- It was thought (d) _____ there exists life on Mars, (e) _____ two viking spacecrafts (f) _____ landed on Mars in 1976 did not provide much evidence of life therE- The pictures sent by them showed (g) _____ the Mars has a sky; (h) _____, the sky is red instead of a blue one like ours. Its gravity is about half (i) _____ strong (j) _____ that of Earth. (k) _____, the atmosphere is also much thinner than our planet. It has deserts, high mountains, canals, volcanoes, craters etc. as well as summer (l) _____ winter. (m) _____, there are no trees, (n) _____ life forms.