Solution
Eukaryotes play important ecological roles on a global scale. They are responsible for global
carbon fixation and marine primary productivity. They are providers for changing climate
processes and form a substantial basis of the marine food web. They have cell walls, which are
made of silica and the largest class of silicifying organisms on the planet at cellular level. They
are also contributors to biogeochemical processes. They vary ecological conditions from and
environmental changes occur by altering the process of cellular metabolism. The response of
organism comes from factors at the cellular level. The way for estimation in changes in cellular
processes, is to monitor modification in gene expression and changes in mRNA transcript levels.