The heart has 2 chambers: The UPPER CHAMBERS are called the and the LOWER CHAMBERS are called the a
valves, septum
b
right, left
c
atrium, ventricles
d
top, bottom

The heart has 2 chambers: The UPPER CHAMBERS are called the atrium and the LOWER CHAMBERS are called the ventricles

Therefore , answer is c

it’s previous models   because when i picked that son of a gun’s answer it was wrong look for previous models because they might make it a different letter  

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.