If you have both parents with long ears and some of the offsprings have short ears, you can say both parents are heterozygous for this. Both have a dominant (long ear), and a recessive allele (short ear).
To prove this, you can draw a Punnett square, and you'll see the probabilities of the offsprings.
Answer:
When resources are limited
Explanation:
If an invasive species is added into a food chain/web, it becomes overpopulated/a pest because it has no natural predators.
It can also disrupt the food chain/web by eating the food supplies of the native organism leading to competitions.
