Which describes pumice and obsidian? a. both pumice and obsidian are coarse-grained intrusive igneous rocks. b. pumice is a coarse-grained extrusive igneous rock, while obsidian is a fine-grained intrusive igneous rock. c. pumice is a fine-grained intrusive igneous rock, while obsidian is a coarse-grained extrusive igneous rock. d. both pumice and obsidian are fine-grained extrusive igneous rocks.

Over time the trees in african have increased in length. many species have had to adapt to this change in order to survive. which of the following is a structural adaptation that has the african giraffe meet this change? question options: the african giraffe has become a faster at running from its predators. the african giraffe's neck has increased in size over the years. the african giraffe have moved to another part of africa. the african giraffe has not adapted and struggles to survive.

Which prevent errors in dna replication? a. helicase enzyme checks the dna for errors. b. each base can attach to only one other type of base. c. ribosome enzymes prevent errors from happening. d. dna contains no complementary base pairs.

What is thought to have caused the mass extinction at the end of the cretaceous period?