<h3><u>Answer;</u></h3>
A. Gas exchanges takes place by diffusion.
B. It is an open system.
<h3><u>Explanation</u>;</h3>
- Most molluscs and arthropods have an open type of circulatory system.
- Open circulatory systems pump blood into a hemocoel with the blood diffusing back to the circulatory system between cells.
- Blood is pumped by a heart into the body cavities, where tissues are surrounded by the blood.
Answer:
Glucose
Oxygen gas
Explanation:
Glucose is a non-metallic carbohydrate substance. It is the monomeric unit of the digestion of complex carbohydrate.
This compound is very important to all lives. The energy needed to power the activities in the body are derived from the compound.
It is made up of carbon, hydrogen and oxygen atoms.
Also, oxygen gas is used by animals for their metabolic processes. The gas combines with glucose to release chemical energy for use in the body. This molecule is purely made up of two atoms of oxygen that are covalently bonded together.
Anytime we breathe, we take in oxygen for use in our body
The carbon footprint can be decreased by a great amount if the incandescent bulbs are replaced with the compact fluorescent bulbs. The compact fluorescent bulbs uses approximately seventy five percent less energy than the incandescent bulbs as they do not use heating mechanism to light. This leads to less emission of the green house gases and thereby reducing the carbon footprint.
Hence, the correct answer is 'option a - replacing incandescent bulbs with compact fluorescent bulbs'.
D. He controlled variables by studying one or two traits at a time
