Answer: A
Explanation: Vaccines create memory cells with a weak version of the pathogen, so when they meet that pathogen again the body can respond more quickly and more efficiently since they have already been exposed to the pathogen.
DNA acts as a sort of set of instructions for building an organism.
In that way, different types of organisms--plants, animals, bacteria, etc.--can all be differentiated through their DNA because it is directly linked to how they function.
Answer:
Ion
Explanation:
An Ion is exactly as stated it bears either a positive or negative charge.
No. The natural selection is when the best suit fits survive. Therefore is not the idea that as an environment changes.
What you meant must be the adaptive advantage of the frogs' lungs. Frogs are considered as amphibians wherein the have this unique ability to reside either on land or in water. Their specialised lungs could be responsible to these which makes them capable of breathing oxygen in water and land.
