The disadvantages of the pyramid of productivity as a representation: The rate of biomass production of an organism is required, which involves measuring growth and reproduction through time. There is still the difficulty of assigning the organisms to a specific trophic level.
Nervous tissue is made up of neurons and supportive cells. Throughout the human body the neurons carry electrical and chemical signals, while nutrition is provided by the supportive cells.
They are little soft bodied insect. They suck the plant's nutritious liquid and if they are in large number, they can kill the plants.
Answer:
organelles are very similar to present-day bacteria, suggesting a common ancestor.
Explanation:
Some evidence suggests that some organelles like mitochondria and chloroplasts within eukaryotes were once used to be independent eukaryotes.
Endosymbiosis theory says that ancestral prokaryotic cells engulfed bacteria like cyanobacteria which with time evolved into mitochondria and chloroplast. Molecular evidence also proves that these organelles were once prokaryotic organisms because they show similar genetic makeup and ribosome type.
So these organelles are similar to present-day bacteria showing that they have a common ancestor.