Biology Questions and Answers
Platyhelminthes
- What are the best known
representatives of the
platyhelminth phylum?
The most popular rplatyhelminthes are worms that causeepresentatives of the
human diseases, like schistosome. The planaria, since taenia and (^) it is
been extensively studied in Biology, is
also well known.
- What is the main external
morphological feature that
differentiates platyhelminthes
from other worms
(nematodes)?
Platyhelminthes are also known as
flatworms ba flat body. This is the main ecause they are worms withexternal
morphological feature that differentiates
them from nematodes (roundworms).
- How many germ layers
originate the body of
platyhelminthes? In relation
to this characteristic how are
these animals classified?
Platyhelminthanimals (remember that cnidarians ares are the first triploblastice
diploblastic),germ layers: ecto i.e., thderm, mey present threeesoderm and (^)
endoderm.
- What are the types of
digestion and of digestive
system of platyhelminthes?
Flatwormssystems and they present e have incomplete digestivextracellular (^)
and intracellulardigestions. complementary
- How are nutrients
distributed by the digestive
system in planarias?
Planariassystem (incom have singlplete) e opening digestivewith ramifications
that transpthe body. ort nutrients to all areas of - How is gas exchange done
in flatworms?
Platyhelminthexclusively by diffusion thres exchange gasesough their (^)
body surface. because all cells are localizeThis is only possibled relatively (^)
near to the exterior since gases diffuse
cell by cell (thworms is a feature that allows this type flat shape of these (^) e
of respiration).
- Poriferans and cnidarians
do not have excretory
systems. Do platyhelminthes
have an excretory system?
Platyhelminthexcretory system mades have a primitivee of flame cells (^)
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