The phrase "and the second involved" is correct and usable in written English.
It can be used when referring to a second item or person that is part of a discussion or situation, often in a comparative or explanatory context.
Example: "We discussed the first option thoroughly, and the second involved a different approach to the problem."
Alternatives: "and the second included" or "and the second pertained to".
The first involved setting up manufacturing facilities there, and the second involved making China a major sourcing location.
The first configuration involved an upright face, and the second involved an inverted face.
The first method involved the use of larger Al2O3 particles, and the second involved increasing the impact velocity of the particles by using specially designed nozzles.
The first stage he characterized as survival, and the second involved putting the e-business strategy in place.
The first collapsed before the opposition of the Polish aristocracy, and the second involved Saxony in a series of wars that nearly exhausted the state.
Two sets of experiments are performed in this study-one set with only granular backfill material (benchmark tests) and the second involved the introduction of a soft zone of tire-derived aggregate above the pipe.
The first involved Trachypithecus, with parental taxa Semnopithecus and Presbytis, while the second involved the clade containing Piliocolobus and Procolobus, Colobus and the ancestor of Asian colobines.
The first involved using molten KOH for crystallographic wet chemical etching to remove surface damage induced by dry etching and simultaneously produce smooth vertical sidewalls; the second involved applying piranha solution (a mixture of H2SO4 and H2O2) for surface cleaning and removal of organic residuals.
The first used cosmids and subcloning to identify the DNA region responsible for BTZ resistance in M. smegmatis while the second involved identification and characterization of BTZ-resistant strains of M. smegmatis, M. bovis BCG, and M. tuberculosis.
The second involved harmonizing, identifying and labelling themes from the notes that had been identified by the authors.
The first focus group consisted of seven fourth year residents (participants A-G); the second involved seven third year residents after they had matched to their fellowship (participants H-N); and the third involved five residents (originally six but one resident was unable to attend at the last minute), some third and some fourth year (participants O-S).
