Both petroleum and coal are made up of complex carbon-based molecules, and both originated with living creatures of some kind. both are vital sources of energy for the modern world and both were formed by geologic processes over millions of years. however, petroleum was mainly formed from the remains of ocean-dwelling microorganisms. coal, on the other hand, originated from decayed vegetation in ancient swamps and bogs. in any case, it took millions of years for both coal and oil to be produced. this is the case because it took that much time for overlying sediments to produce the unimaginable heat and pressure that would one day allow us to harvest these energy resources. what is one clue word or phrase in the passage that indicates a contrast? a. both b. because c. however d. in any case

Why it's time to lay the stereotype of the 'teen brain’ to rest 2. part b: which detail from the text best supports the answer to part a? a “brain deficits don’t make teens do risky things; lack of experience and a drive to explore the world are the real factors.” (paragraph 1) b “according to this theory, the prefrontal cortex, the center of the brain’s cognitive-control system, matures more slowly than the limbic system, which governs desires and appetites including drives for food and sex.” (paragraph 5) c “in experiments that mimic the well-known marshmallow test, in which waiting for a bigger reward is a sign of self-control, adolescents are less impulsive than children and only slightly more so than adults.” (paragraph 12) d “the majority of adolescents do not die in car crashes, become victims of homicide or suicide, experience major depression, become addicted to drugs or contract sexually transmitted infections.” (paragraph 14)