A very strong relationship. I'll take the easiest example :the bees. They are so important for our planet. Without them, we and all living creatures on earth would be on track to dispariton. Let me explain why. At first, the bees need the nectar from flowers to make honey ( source of food ). As they pollen from flower to flower, they transport pollen on their tiny little legs and in this way, they help the plants to reproduce themselves. If, for some reason, there will be no more bees. Plants and flowers will not thrive, plants will be eaten without having contribued to the productivity of the species and they will go out. No plants, no more veggies or fruits for herbivorous and humans, no more herbivorous no more food for carnivorous, etc. Also, without plants, there will be less oxygen on our planet. Slowly the fauna and flora will die on earth and then it will be our turn. That is why relationships with plants and insects are so important. Plants produce oxygen for all of us and they are a natural and healthy source of food and insects help plants to survive and thus save the species.
The minimum legth of a codon could be two. If it was only one of the 6 nitrogeneous bases in a codon, we'd only have 6 possible amino acids. If we have, though, a combination of two amino acids out of the 6 nitrogeneous bases, we would have then 36 possible combinations (6 possibilities for the first position × 6 possibilities for the second position) that would allow the existence of the 20 different amino acids.
In the human case, for example, with only 4 nitrogeneous bases, a combination of two amino acids would be insufficient (4×4=16) for the 20 amino acids.
<span>A heterozygous individual is if a mutation occurs in just one copy of the gene.
If both copies of the gene are mutated than the individual is homozygous</span>
Modern day whale species, have very small pelvic bones in comparison to their body size, and also they are useless. This is because this bones in the whale body are remnants from the time when their ancestors were land dwelling creatures, thus they had legs as the typical land mammal has. But during their evolution, as their ancestors were starting to adapt more to the water, the legs started to disappear, but the bones inside of the body remained, even though they were of not use. Even though millions of years had passed since this bone is useless, it still exists, and the reason for that is that there hasn't been any evolutionary pressure for it to not exist, since it is not causing any disadvantage into the movement and lifestyle of the whales.