The correct answer is mRNA.
mRNA or messenger RNA is synthesized during the process of transcription, from DNA molecule which is used as a template. mRNA contains information about protein synthesis (translation) in the form of nucleotide triplets or codons.
In the example above: reference book is DNA molecule (template for copies), copies are mRNA, wood is amino acids (building blocks) and doghouse is protein.
Answer:
Mitosis is the reproduction of tissue cells. While Meiosis is the reproduction of one diploid cell into 4 haploid cells.
Explanation:
A. Organic compounds - C₃N₂H₄ , C₆H₅F and C₁₂H₂₂O₁₁
Organic compounds are compounds which have Carbon except few compounds such as carbon dioxide, cyanide. Other than Carbon, other elements also present such as Hydrogen, Oxygen and Nitrogen. But Carbon is considered as the main element of organic compounds.
B. Inorganic substances - AIBr₃ , CrO₃ and <span>H</span>₂<span>O</span>₂
Inorganic substances are the compounds which do not own C-H bonds. Most inorganic compounds do not have carbon as their element except few. (Cyanides, carbon dioxide, carbon monoxide and so on are considered as inorganic although they have carbon).
The writing materials,the envelopes and the stamps are all made of paper and this led to a great waste as the papers have to be disposed after use. This is not the case with electronic mails. Electronic mails do not need paper at all and it has drastically reduce the amount of papers that is used in writing letters.
I hope this helps :)