If genes play a role in determining tobacco use, identical twins-who share the same genes-will be more similar in their use of tobacco than fraternal twins, who share roughly half of their genes.
(genes; play; a role in determining tobacco use) (identical twins; share; the same genes) (identical twins-who share the same genes; will be; more similar in their use of tobacco than fraternal twins) (fraternal twins; share; roughly half of their genes)
genes identical twins identical twins-who share the same genes fraternal twins
play share will be share
a role in determining tobacco use
the same genes
more similar in their use of tobacco than fraternal twins
roughly half of their genes