Answer:
At the close of the nineteenth century, Thomas Edison was working on perfecting his system of direct current (DC) for electric power distribution. Meanwhile, the inventor and physicist Nikola Tesla was discovering the benefits of his competing alternating current (AC) system.
Explanation:
Receptors in muscles provide the brain with information about body position and movement. The brain controls the contraction of skeletal muscle. The nervous system regulates the speed at which food moves through the digestive tract.Your muscular system is closely connected to the nervous system. That makes sense since you usually have to think before you can move. Even though thinking is not always involved, the neurons of the nervous system are connected to most of the cells in your muscular system.
Viruses are the microorganisms who needs to infect the living host cells, in order to replicate or reproduce. These infectious agents are capable of injecting and infecting all the life forms present, including the plants, animals and bacteria. The viruses were not among the first organisms to evolve as in order to replicate themselves and continue through the time they needed other organisms' cell.
Hence, the correct answer is 'viruses have to infect a living cell in order to reproduce'.
Answer:
Arginine
Explanation:
The biochemical pathway for synthesis of arginine from its precursor includes the formation of ornithine from precursor. Ornithine serves as precursor for formation of citrulline which is then converted into arginine.
The "arg-3" mutants of Beadle and Tatum experiment were defective in the gene that code for the enzyme required to convert citrulline into arginine. These mutants could grow only when arginine was supplemented in the medium.
Seafloor spreading occurs when two plates diverge