How are increasing levels of co2 responsible for warming the surface of earth?

a. co2 traps the heat of the sun in earths atmosphere.

b. co2 is used up by plants during photosynthesis

c. co2 dissolves in larg bodies of water such as oceans and seas

d. co2 enters the soil by way of decaying organisms

e. co2 is constantly moving through all of earths spheres

The correct answer is option A. CO2 traps the heat of the sun in earths atmosphere.

Carbon dioxide gas has the ability to trap the heat of the sun rays near earth's surface. This is known as green house effect. This is the reason why earth's atmosphere remains warm even in the absence of sunlight i.e. during evening and night. The heat which is trapped by CO2 persists in the environment rather than dissipating back into the space. It also means that earth would have been less warmer without an atmosphere because it is the atmosphere of earth which has CO2 and other green house gases.

organisms that lack symmetry are called asymmetrical and belong to phylum porifera/sponges.

organisms with specialized stinging cells belong to phylum cnidaria. stinging cells are called cnidoblast cells.

cnidarians show two morphological forms : polyp (sessile) and medusa (mobile)

filter feeding is observed in porifera members.  

alternation of generation is observed in coelenterata or cnidaria. there is alternation of asexual polyp form and sexual medusoid form. it is also referred as metagenesis.