D.) = 1.)
A.) = 3.)
C.) = 2.)
B.) = 4.)
Answer:d)introns; exons
Explanation:Introns are the non-coding portion of the DNA. They do not code for a gene that can be expressed hence the need for them to be removed from the coding genes(Exons). The exons are then joined together after the introns have been removed to create a sequence of amino acids.
The experiments demonstrate the movement of pollutants through the ground water.
The sand and gravel make up the ground the water represents the ground water. The food coloring represents the pollutants.
The ocean is the largest ecosystem.
The sign of good health in an animal is bright eyes.
Explanation:
The signs that usually is seen in a healthy animal, is its ability to stand straight and have a keen observation. The Animal will have bright alert eyes.
A healthy animal has quick movements. It gets up quickly if its sitting down. The respiration of the animal will be slow and regular.
The saliva will not be dripping from the animal's mouth. It will have a smooth and shiny coat and its nose will not have any discharge but remain dry.
Any sign of rapid breathing or dull inert eyes, etc means that the animal is not healthy and is sick. A healthy animal acts calmly and does not exhibit any anxious behaviour.