Which of the following provides astronomical evidence for the age of the earth?
movement of galaxies
comparative anatomy
molecular clocks
radioactive dating of fossils

Option (4)

Explanation:

Fossils are the dead remnants of ancient flora and fauna that are buried millions of years ago. These fossils are found to be embedded in the sedimentary rocks. Fossils are important because they help in determining the age of the rocks.

The fossils are often dated by different radioactive dating methods, that have different half-lives.

Radioactive dating methods are defined as the methods that determine the age of the rocks and other objects by dating them. The decay rate of these radioactive isotopes must be known to calculate the age. For example, the Carbon-14 dating method.

These fossils are very much helpful because different fossils belong to different time periods. By dating these fossils and the rocks containing them (including other astronomical bodies), one can determine the age of them. The age of the earth is also estimated by using these radioactive dating methods.

Hence, the correct answer is option (4).

increase soil erosion                                             reduce soil erosion

cattle grazing                                                         hydroseeding

deforestation                                                         contour plowing

                                                                                planting vegetation

plant roots basically hold the top soil

together and stop soil erosion because

in such situation top soil is not removed

during flood but cattle grazing causes

soil erosion because cattle consume the

grasses and herbs and top soil is exposed.

same situation occurs because of

deforestation, the trees and plants are cut

down to expose top soil which causes soil

erosion