Which of lamarck's ideas turned out to be true? which turned out to be false?

The fact that Lamarck thought that organisms could adapt in their lifetime and evolve to become "more perfect" is false because evolution happens over generations and there is no one definition of perfect, animals mainly evolve to improve their fitness. Lamarck also thought that animals could pass these traits on to their next generation consciously. So these thoughts were all false, but the fact that he was in the mindset that animals could evolve was true. That's about all that was true though. 

Hope this helps!

Abay where the river empties into the sea

Yes yes yes very good