Questions

Among the given options Brass is not a compound. Since it is an alloy, it is a mixture. It is a mixture of copper and zinc.

The smallest part of a compound is called a molecule. It has a unique composition that is always the same.

Compound is a substance that consists of two or more elements. 

Deoxyribose, which is a pentose, and a phosphate group are the two molecules together form the two sides of the DNA i.e, A sugar (deoxyribose) and a phosphate.

DNA is a double-stranded molecule twisted into a helix (think of a spiral staircase). Each spiraling strand, comprised of a sugar-phosphate backbone and attached bases, is connected to a complementary strand by non-covalent hydrogen bonding between paired bases. The bases are adenine (A), thymine (T), cytosine (C) and guanine (G). A and T are connected by two hydrogen bonds. G and C are connected by three hydrogen bonds.

Catfish

Round-robin (RR) is one of the algorithms employed by process and network schedulers in computing. It falls under the category of Preemptive scheduling. In computing, the running task is interrupted for some time without requiring its cooperation and resumed later when the priority task has finished its execution. This is called preemptive scheduling. 

The logic in the challenge is

 81x6 = 9x6 = 54

144x7=84

Similarly, 64x8 = 8x8 = 64.