Answer:
DNA. genetic material passed down generationa
The brain it sends messages to the spinal cord which aids for the movement of the body
spinal cord aids for movement
ok so i dont know much about this but but im going to try my best.
so i did a bit of research about what all those birds have in common like you asked for and so they birds really dont have that much in common, so i went on a PREZI and i did some more reasearch i took some pictures to maybe help you.
im not sure if this helped if i didnt do it correctly just lemme know and ill do more research
ok so i added more research to this, look at the pictures, it is the EXACT answer to your question, if you need more research lemme know fam
Answer:
Directional selection
Explanation:
Natural selection is of three types :
1. Stabilizing selection: in this type of selection, genetic diversity decreases as the population stabilizes on a particular trait value. Here the mean phenotype is favored.
2. Disruptive selection is a type of selection in which extreme values for a trait are favored over the mean values thus increasing the genetic variance by favoring two extreme phenotypes.
3. Directional selection is a type of selection in which a single phenotype is favored which is of the extreme phenotype over the mean phenotype.
In the given case it can be observed that the selection is favoring long necks in case of giraffes and hence, this is an example of directional selection.