I think the deficiency of dedicated respiratory and circulatory systems in Planarians does not cause a problem because none of their cells are far removed from the gastrovascular cavity or from the external environment. Planarians are free-living flatworms and form the class Turbellarians in the Phylum Platyhelminthes. Flatworms have three tissue layers, that is the ectoderm, mesoderm, and endoderm.
Because an organism needs even more cells to help it function better and change as it grows (like metamorphosis and yes, puberty :p) and if the same amount of cells stay then the organism's cells will be functioning and working harder.....so cells divide so many different ones can continue to work on different parts of the organism as it grows and changes. Plus it'd be weird if we only had like 1 thousand cells in our body from mothers' pregnancy the size of hi-polymer erasers (the big ones)..........
The following option are correct:
1. There will be interspecific competition between foxes and tigers.
Competition for food between animals of different species is called interspecific competition while that between the same animal species is called intraspecific competition.
2. The energy received at the tropic level of carnivores will be less than the usual amount.
The energy received at the trophic level become reduced because the amount of food available for the carnivores has been reduced.
3. There will be decreased biomass at the trophic level of carnivores.
Decrease biomass will occur at the trophic level of carnivores because, those carnivores that can not survive the food reduction problem will die off.
