An open flame or burning flame
Answer:
Access. A basic feature of any greenhouse is access. ...
Vents. One of the first greenhouse features necessary is a means of controlling the climate – most importantly, venting excess heat. ...
Fans. Fans inside a greenhouse are necessary for two basic functions. ...
Rollup Sides. ...
Heaters. ...
Shelves and Benches. ...
Water. ...
Electricity.
Explanation:
theres more but these are the important ones .
The general theory is that mitochondria and chloroplasts began initially as separate cells that were "eaten" by larger cells, but not digested and simply passed on due to their advantages.<span />