which two is the nematode body
Answers
Explanation:
Nematodes are bilaterally symmetrical, elongate, and usually tapered at both ends. Some species possess a pseudocoel, a fluid-filled body cavity between the digestive tract and the body wall. Like arthropods and members of six other phyla, nematodes secrete an external cuticle that is periodically molted.
Explanation:
The nematodes (UK: /ˈnɛmətoʊdz/ NEM-ə-tohdz, US: /ˈniːm-/ NEEM- Greek: Νηματώδη; Latin: Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes),[2][3] with plant-parasitic nematodes being known as eelworms.[4] They are a diverse animal phylum inhabiting a broad range of environments. Taxonomically, they are classified along with insects and other moulting animals in the clade Ecdysozoa, and unlike flatworms, have tubular digestive systems with openings at both ends. Like tardigrades they have a reduced number of Hox genes, but as their sister phylum Nematomorpha has
kept the ancestral protostome Hox genotype, it shows that the reduction has occurred within the nematode phylum
Nematode species can be difficult to distinguish from one another. Consequently, estimates of the number of nematode species described to date vary by author and may change rapidly over time. A 2013 survey of animal biodiversity published in the mega journal Zootaxa puts this figure at over 25,000.[6][7] Estimates of the total number of extant species are subject to even greater variation. A widely referenced[8] article published in 1993 estimated there may be over 1 million species of nematode.[9] A subsequent publication vigorously challenged this claim on the grounds that it is unsupported by fact, estimating the figure to be as low as 40,000 species.[10] Although the highest estimates (up to 100 million species) have since been deprecated, estimates supported by rarefaction curves,[11][12] together with the use of DNA barcoding[13] and the increasing acknowledgment of widespread cryptic species among nematodes,[14] have placed the figure closer to 1 million species