The most likely reason for the development of resistance against pesticides in insects damaging a crop is   
1. Genetic recombination
2. directed mutations
3. Acquired heritable changes.
4. Random mutations 

In genetic drift, the term “genetic bottleneck” means:
1. reduction in allele frequencies or richness
2. random change in allele frequency by chance alone
3. sudden increase in the number of individuals
4. reproductive isolation of the population

De Vries gave his mutation theory on organic evolution while working on   
1. Oenothera lamarckiana
2. Drosophila melanogaster
3. Pisum sativum
4. Althea rosea 

de Vries based his “Mutation Theory” on his observation on :
1. Pisumsativum
2. Drosophila melanogaster
3. Oenotheralamackiana
4. Coenorhabditiselegans