Preliminary contracts are those contracts made before the formation of the company, whereas the contract entered by a company after incorporation but before it is entitled to commence business is termed as provisional contracts.
Primers are
chemically synthesised oligonucleotides to which Taq polymerase adds deoxyribonucleotides on its 5' end
chemically synthesised oligonucleotides that are complementary to specific regions of template DNA
chemically synthesised, autonomously replicating circular DNA molecules
sequences present in the genes of our interest