In order for gas to leave a planet it needs to be hot enough and to overcome the planets gravity. The outer planets are colder and are very big compared to earth.
Excess Nitrates in the water supply
A bone is tissue. It forms a part of the skeletal system which is made up bones, joints, ligaments and cartilage. Cells work together in groups known as tissues. A tissue is defined as a group of similar cells working together to carry out a certain task. Examples are skin, bone, blood. Tissues in turn are grouped together to form organs. An organ is defined as a group of tissues that work together to carry out a certain task . Examples are heart, lungs, liver.
