Mars has almost every feature ……………………… (that / what / this) earth has. Scientists have already discovered hills, craters, and dry riverbeds ……………………. (on / in / at) the Red Planet. New images now show that some parts of the Martian landscape might also be dotted ………………………. (with / about / to) caves. If confirmed, these caves could be ………………………… (among /between) the only places on Mars to find evidence of past or present microbial life.

Certain pictures ………………………… (taken / taking / took) by the Mars Odyssey spacecraft showed seven possible entrances to caverns. The entrances are dark, circular structures, ………………………. (measuring / measured) between 100 meters and 250 meters across. Scientists don’t know ……………………….. (how / what / that) deep the caves are. The data do show, ……………………. (though / as though / although), that temperatures within the structures are constant and different ……………………………… (from / with / in) temperatures of the surrounding land. That suggests that they are indeed cave openings.

 Answers

Mars has almost every feature that earth has. Scientists have already discovered hills, craters, and dry riverbeds on the Red Planet. New images now show that some parts of the Martian landscape might also be dotted with caves. If confirmed, these caves could be among the only places on Mars to find evidence of past or present microbial life.

Certain pictures taken by the Mars Odyssey spacecraft showed seven possible entrances to caverns. The entrances are dark, circular structures, measuring between 100 meters and 250 meters across. Scientists don’t know how deep the caves are. The data do show, though, that temperatures within the structures are constant and different from temperatures of the surrounding land. That suggests that they are indeed cave openings.