6. Sequence the rock layers below from oldest to youngest: H. E.4A.5 A
B
с
D
E
a. CBADE
b. CBDEA
c. CBEAD
d. CBEDA

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

a. by using fur or clothes to trap heat energy near the body

answer: andy garner, a 17-year-old who decided to become a human guinea pig in 1965 and go without sleep for 11 days. by the second day his eyes had already stopped focusing, and he lost the ability to identify objects by touch. by day three he was moody and uncoordinated and by the end he had trouble with short term memory and had even started hallucinating.

and a rare genetic mutation called fatal familial insomnia, where people can’t sleep at all, gets progressively worse over months or years and leads to dementia and death.

a devoted soccer fan died after staying awake 48 hours to watch the world cup, she said. ‘while his untimely death was due to a stroke, studies show chronically sleeping fewer than six hours a night increases stroke risk by 4 1/2 times compared with those getting a consistent seven to eight hours.'

*shorten it up as your wish*

(i have divided it into 3 simple paragraphs)