A(n) called asthma occurs when the muscles that surround the bronchioles constrict.

What was the land like over 500 million years ago? what was under the sea?

Which statement about relative potential energy of electrons is correct? a. an electron in the 2 p orbital of the second electron shell has more potential energy than an electron in the 2 s orbital of the second electron shell. b. an electron in the 2 p orbital of the second electron shell has more potential energy than an electron in the 3 p orbital of the third electron shell. c. an electron in the 3 p orbital of the third electron shell has more potential energy than an electron in the 2 p orbital of the second electron shell.

Some substances but not other can cross the (blank) membrane of a cell