Living things:-
-Living things are made of cells.
-Living things have and use energy.
-Living things grow and develop.
-Living things reproduce.
-Living things respond to their environment.
-Living things adapt to their environment.
Answer:
Neighboring cardiac muscle cells in the walls of heart chambers have specialized cell-to-cell contacts that electrically and mechanically link the cells together, permitting the immediate passage of muscle impulses. These cell-to-cell contacts are called <u>intercalated discs.</u>
Explanation:
Intercalated discs can be described as unique structures present between the cardiac muscles of the heart. The intercalated discs play a major role in making the cardiac muscles contract in a rhythm so that the heart can pump blood in a regular fashion and it hence regulates the effective functioning of the heart. The intercalated discs are the structures that join on cardiac muscle to another and is involved in the transmission of chemical messages between them.
It was exposed to oxygen. This is called oxidation and it's a chemical reaction, meaning it can't be reversed.
Answer: The greenhouse gas emissions from the extraction of bitumen and the use of large quantities of water.
Explanation:
Bitumen is a natural flammable organic matter formed from kerogen in the process of petroleum generation, which is soluble in carbon disulfide. Asphalt and mineral wax are examples of hydrocarbons which are part of bitumen. Conventional oil is extracted by wells while <u>oil sands deposits are extracted using surface mining sectioning techniques, or are flowed to wells by in situ techniques that reduce bitumen viscosity by steam and/or solvents.</u> So, unlike crude oil extracted in oil wells, bitumen requires an open-pit mining operation, in which large tracts are washed with a mixture of water and chemicals to separate the bitumen from a mixture of sand and clay.
Two consequences of this practice are:
- The greenhouse gas emissions from the extraction of bitumen are larger than the extraction of conventional oil. The emissions produced contribute to enhance the greenhouse effect and cause global warming. The greenhouse effect occurs when certain gases retain part of the energy emitted by the earth's soil when heated by the sun's radiation. This phenomenon occurs naturally, and thanks to it, the average temperature of the Earth is about 14º C (57.2 °F). The problem occurs when these greenhouse gases increase in the atmosphere and the amount of energy that is not released into space also increases and, with it, the Earth's temperature.
- The extraction of bitumen from oil sands requires the use of large quantities of water, and even though water used here can be recycled, only a small amounts is returned to the natural cycle. Also, spills from the transportation of the oil could damage soils and waterways, increasing water pollution. This toxic water could get into surface.
