Mode of transport available, especially in underdeveloped or inaccessible regions. Although humans are able to walk without infrastructure, the transport can be enhanced through the use of roads, especially when using the human power with vehicles, such as bicycles and inline skates. Human-powered vehicles have also been developed for difficult environments, such as snow and water, by watercraft rowing and skiing; even the air can be entered with human-powered aircraft. Land transport covers all land-based transportation systems that provide for the movement of people, goods and services. Land transport plays a vital role in linking communities to each other. Land transport is a
History of the battery 1860s, a Frenchman named Callaud invented a variant of the Daniell cell called the gravity cell. This simpler version dispensed with the porous barrier. This reduced the internal resistance of the system and, thus, the battery yielded a stronger current. It quickly became the battery of choice for the American and British telegraph networks, and was used until the 1950s. The gravity cell consisted of a glass jar, in which a copper cathode sat on the bottom and a zinc anode was suspended beneath the rim. Copper sulfate crystals would be scattered around the cathode and then the jar would