In the origin of eukaryotes, endosymbiosis: a. describes the engulfing of a photosynthetic bacterium that ultimately gave rise to mitochondria b. most likely began with the endosymbiont entering the host cell through the endomembrane system c. most likely began with a heterotrophic endosymbiont entering the cell as undigested prey or as an internal parasite d. is thought to explain the origin of the nucleus

i think it is true in my reasonment ..

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.

answer: national resource conservation services

national resource conservation services is the us. based approach that provides technical and financial assistance for natural resource management. nrcs society in conservation of resources by involving in activities like farmland protection, flood prevention, watershed protection, urban conservation, conserves economic and environmental conditions. it conducts soil surveys and implements the policy of natural resources management on the society.

colors do exist. the color of the sky is actually violet; humans percieve the color of the sky as blue.