Questions

When two or more chemical species combine to form a single product, the reaction is said to be synthesis reaction. It is also called as Direct Combination reaction.

Here in the given options, Sodium (Na) combines with Chlorine (Cl) to form a more complex single product Sodium Chloride (NaCl).

Therefore the answer for What travels around the world but stays in one spot is STAMP or any other thing that acts as a stamp does.

Ex. the letter in the envelope etc...

Since, Several things have the possibility, but the word travel evokes that it would move. 

Agriculture would be a good example of a purely competitive industry.

Expendable properties are those properties that are consume in use or that lose their identity in use. It also include those properties that become an integral part of other property when put to use and those properties which have an expected service life of less than one year.

DNA is made of nucleotides. And these Nucleotides are made of a pentose sugar deoxyribose, a phosphate, and a nitrogen-containing bases.

Hence, the given statement 'Nucleotides are made of a pentose only' is FALSE.

Anemometer is the instrument that is used for measuring the speed of wind or any gas currents.