Because the molecules that are being transported is moving against its concentration. gradient. in other words, its moving from where it's low in concentration to where it's high in concentration.
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
Circulatory system;<span>The circulatory </span>system<span> circulates blood through the </span>body<span>, </span>supplies<span> cells with </span>oxygen<span> and </span>nutrients<span> and</span>removes waste<span> products. Organs: heart, arteries, veins. ... The respiratory </span>system supplies<span> blood with
</span>oxygen<span> in the lungs and </span>removes<span> carbon dioxide.</span>
Epithelial tissue. This type of tissue is made up of cells that are closely packed and arranged in one or more layers. Epithelial tissues cover internal and external body surfaces. They have a high regenerative capacity.and has many functions including, protection, absorption, secretion, sensation and excretion.