Which human action does not alter the earth's landscape?

Simple astronomical telescope the objective lens has a focal length of 75 cm and that of a piece of 5cm of the lenses are 18 cm apart when will be final image of a distant object before

What can you learn about precipitation levels in south america from this map? brazil is experiencing a drought.it rains more in higher altitudes.peru received the highest level of rain.venezuela got less than 25 cm of rain. 

Which revelation resulted from the observation of the spectrum of different galaxies? a. there were more galaxies whose spectrum was blueshifted b. there were no galaxies whose spectrum was redshifted c. there were more galaxies whose spectrum was redshifted d. there were no galaxies whose spectrum was blueshifted