Answer:
A.
Explanation:
It is A because the diagram for choice A shows correctly how cellular respiration produces energy and releases carbon dioxide and water as byproducts(CO2). And it also shows how photosynthesis release or produces oxygen gas (O2)
Well for starters, producers are living organisms that produce their own food. Like plants. And plants ironically provide us humans with oxygen as they live off of the carbon dioxide we produce. Some plants are also main vegetables that we eat, so put simply, a world without producers would be practically oxygen-less and vegetable-less.
Answer: B
Like the nervous system, the endocrine system is a regulatory system. However, instead of using electrical impulses for signaling, it produces and uses chemical signals called hormones, which travel through the bloodstream and control the actions of cells and organs.
A)Demographic; because the census studies things such as births,death, and even disease which show changes in human population
