Echinoderms, they are among the most common invertebrate animals in the marine environment of virtually any part of the world, among them we can find species such as sea cucumber , salmon and cod fish, they have chamois cloth like outer layer, then we have the Crinoids, another example of marine species with feather, popularly they are called sea lilies and feathery stars, they have a solid calcite skeleton; they were so abundant in the paleozoic seas that their remains formed large limestone thicknesses.
Echinoderms which are among the very simple invertebrate animals in the aquatic ecosystem of essentially any part of the world and also among them we can search species such as sea cucumber, salmon and codfish, they have a chamois cloth-like outer layer, then we have the Crinoids.
There is another example of aquatic species with a feather, regularly they are known as sea lilies and feather stars, they have a hard calcite skeleton they were so plentiful in the Paleozoic seas that their remains made large limestone thicknesses.
You would have to be very careful of cross-contamination. That means you would have to work very carefully and precisely with protective clothing, ensuring that none of your DNA (from skin or hair or even trace) gets into the sample you are working with
You would have to be very careful to check and record samples properly to ensure nothing got mixed up or mislabeled and this could be disastrous for criminal cases
All the material is very precious and sometimes only one sample exists, so you have to avoid making any mistakes. Experiments can't always be repeated.
"Survival of the fittest" is the one among the following choices given in the question which is an aspect of Darwin's theory that is shown as an example in this scenario. The correct option among all the options that are given in the question is the third option or option "c". I hope that this answer has helped you.
