<span>a. Fish have a single central heart; earthworms have several hearts.
</span>
Multi cellular organisms are made up of billions of cells each specialized to a unique role and these cells are organized into structural and functional units such as tissues and organs.
For each cell and organ to function optimally, it requires oxygen and nutrients and needs carbon dioxide and metabolic waste taken away in a continuous, never ending process.
<span>A mechanism is needed to accomplish the important function of transporting the relevant materials to and from the cell. The circulatory system fits this bill splendidly. It is a specialized organ system which allows blood and lymph to flow through the entire body carrying nutrients such as glucose, amino acids and electrolytes as well as oxygen to each cell, at the same time carting away carbon dioxide and all sorts of metabolic waste over to excretory organs to be expelled from the body.
</span>
Answer:
Its A . serve as a food source for other organisms .
Explanation:
<em>h</em><em>o</em><em>p</em><em>e</em><em> </em><em>i</em><em>t</em><em> </em><em>h</em><em>e</em><em>l</em><em>p</em><em>s</em><em> </em>
Answer:
Nitrogen cycle
Explanation:
Nitrogen fixation is the process by which atmospheric nitrogen is converted by either a natural or an industrial means to a form of nitrogen such as ammonia. In nature, most nitrogen is harvested from the atmosphere by microorganisms to form ammonia, nitrites, and nitrates that can be used by plants.
Answer:
Aerobic respiration can be described by the following word equation: glucose + oxygen gives carbon dioxide + water (+ energy) This means that glucose and oxygen get used up while carbon dioxide and water are made. The chemical energy stored in the glucose molecule is released in this process.
Explanation:
Answer:An open system exchanges matter and energy with its surroundings (for example, an ecosystem). ... Strictly, closed systems do not occur naturally on Earth, but all the global cycles of matter, for example,the water and nitrogen cycles, approximate to closed systems.Sep 18, 2020
Explanation:
