A vestigial organ, something that has yet to fall prey to evolution, but no longer serves a purpose, or the purpose it used to serve.
Explanation:
you just need to know that :
population density = no of ( what is asked) / land area.
I think the answer is the last one; Flame bulb; flat worm.
A flame bulb or a flame cell is a specialized excretory cell found in the simplest fresh water invertebrates, including flatworms, rotifers and nemerteans; these are the simplest animals to have a dedicated excretory system. Bundles of flame cells are called Protonephridia.
Answer:
an individual animal, plant, or single-celled life form.
Over utilisation of resources is the unlimited and careless use of any resource or utility. It refers to the excessive use of something to a point that in return we are deteriorating the resource. It can also be termed as exploitation or sustainable use. In the 21st century, we must focus on sustainable development and not over-utilisation of resources.
