Jacob asks his little brother boris to play a game of chess with him. as boris has never played chess before, jacob explains the rules of the game to him. what type of long-term memory has primarily jacob to recount his knowledge of chess to boris?

The answer is "semantic memory".

Semantic memory alludes to a bit of long haul memory that forms thoughts and ideas that are not drawn from individual experience. Semantic memory incorporates things that are regular learning, for example, the names of hues, the hints of letters, the capitals of nations and other fundamental certainties gained over a lifetime.  

The idea of semantic memory is genuinely new. It was presented in 1972 as the aftereffect of coordinated effort between Endel Tulving of the University of Toronto and Wayne Donaldson of the University of New Brunswick on the effect of association in human memory.

explanation:

allergens: overstimulate the nerve system

neurotics: attack nerve cells

mutagens: damage or otherwise alter dna sequence

generators: cause defects during growth and development  

carcinogens: cause unchecked cell growth

i hope you get the idea according to me these are the effects that happened.