Complex sentence: Other critics note that in human populations twins are not a random sample of the population-They are not even a representative sample Record, R. G., McKeown, T., & Edwards, J. H. (1970).
Split into simpler sentences: Other critics note that in human populations twins are not a random sample of the population. Indeed, they are not even a representative sample Record, R. G., McKeown, T., & Edwards, J. H. (1970).