Answer to Question 1
Two kinds of formations hint at water flowing over the surface. Outflow channels appear to have been cut by massive floods carrying as much as 10,000 times the volume of water flowing down the Mississippi River. In a matter of hours or days, such floods swept away landscape features and left outflow channels. The number of craters formed on top of the outflow channels show that they are billions of years old. The valley networks look like meandering riverbeds that may have formed over long period. The valley networks are also located in the old, cratered southern hemisphere, so they must be very old as well. There are other signs that water has flowed on the Martian surface, some of which may be only a few years old
Answer to Question 2
Most of the surface of Venus consists of low, rolling plains and highland regions. Those rolling plains appear to be large-scale smooth lava flows; whereas the highlands are regions of deformed crust. Lava flows seem to have completely resurfaced Venus within approximately the past half-billion years. Signs of volcanism dominate the surface of Venus. Lava channels are common, and they appear similar to the sinuous rilles visible on Earth's Moon. Scientists have identified these features from radar imaging of the surface using instruments on satellites orbiting the planet.
Water Molecules Surround Ions
Microscopic photo taken by Opportunity showing a gray hematite concretion, indicative of the past pr
The Water Cycle
Pineal Gland, Located on the Dorsal Surface of the Midbrain
The features found in a long bone.
Common sequence features in integrated retroviruses and other eukaryotic transposable elements