The sudden death of brain cells when their blood supply is interrupted is called
a. a heart attack.
b. a stroke.
c. hypertension.
d. atherosclerosis.

Option B, a stroke

Explanation:

A stroke is caused by an interrupted blood supply which leads to the death of brain cells. The strokes are of two types –

a)Ischemic attack– In this a blood clot causes blocking of blood vessel. Ischemic attack is of two types –  

1.Thrombotic – This occurs primarily due to blood clotting in any vessel or artery

2.Embolic. This occur when a part of thrombus travels from its original site and blocks some other artery  

b)Hemorrhagic stroke – In this a blood vessel burst inside a brain thereby causing brain hemorrhage.

the transfer for conduction is the heat transfering from the liquid to the spoon

the transfer for convection is the heat rising from the liquid to the air

the transfer for radiation is the heat going through the sides of the cup and to the air

at least that is what i would do

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

: -)