Choose all the answers that apply.

How is carbon dioxide returned to the atmosphere?

burning of fossil fuels
respiration
photosynthesis
nitrification
denitrification
decomposition

A. burning of fossil fuels

B. respiration

Explanation:

Fossil fuels such as petrol, diesel and coal are used in the movement of cars. These fuels are burnt inside the engine of vehicles and carbondioxide is released. Respiration is energy releasing process in which energy is released in the form of Adenine tri phosphate. In respiration, carbondioxide is released when glucose is broken down inside the mitochondria of the cell with the addition of oxygen.

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.