In 1871, a Russian Chemist, Dimitri Mendeleev, gave a useful scheme for classification of elements. He presented the first regular periodic table in which elements of similar chemical properties were arranged in eight vertical columns called groups. The horizontal rows of table were called periods. He arranged elements in ascending order of their atomic masses and found that elements having similar chemical properties appeared at regular intervals. This observation was called Periodic Law.
Contact transmission<span> is the most common form of </span>transmitting<span> diseases and virus. There are two types of contact </span>transmission<span>: </span>direct<span> and </span>indirect<span>. </span>Direct<span> contact</span>transmission<span> occurs when there is physical contact between an infected person and a susceptible person. Cheers and god bless
AlexFray555
Please put brainliest!</span>
Answer:
customary Is the required system