In bacterial cells, the replication of dna begins at a specific site called the of replication, and proceeds in both direction around the circular dna until a specific site is reached

it has one origin of replication, but it proceeds in two directions - d)

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".