What did Charles Darwin mean when he started that sone organisms were " more fit " than other organisms?

Witch one is it soo it the the question b.a,b,c,d

Answer this asap. why did the americans go to china? a. trading b. exploration c. land d. live stock

If a volcano’s magma is high in silica, the volcano will probably a. erupt quietly. b. remain dormant. c. erupt explosively. d. produce dark-colored lava.