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Which of these does not have respiratory and circulatory system (a) annelids (b)nematods (c)insects (d)mollusca?

Which of these does not have respiratory and circulatory system
(a) annelids
(b)nematods
(c)insects
(d)mollusca?

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Answers (5)

isaaq
1 month ago
Answer is B) Nematodes.
The Nematoda phylum mostly contains of roundworms or worm-like organisms. They have a digestive, nervous and reproduction systems, but they lack a circulatory and respiratory. Nematodes have the ability to give off carbon dioxide and pick up oxygen molecules from the moist environment. This is only possible due to their high surface area compare to there small body. Just like the Cnidaria they are able to use their structure in a moist environment to make up for their lungs.
mizta smart
1 month ago
B) Nematodes.
The Nematoda phylum mostly contains of
roundworms or worm-like organisms. They
have a digestive, nervous and reproduction
systems, but they lack a circulatory and
respiratory. Nematodes have the ability to
give off carbon dioxide and pick up oxygen
molecules from the moist environment. This
is only possible due to their high surface
area compare to there small body. Just like
the Cnidaria they are able to use their
structure in a moist environment to make
up for their lungs.
Gaby
1 month ago
Answer is B) Nematodes.
The Nematoda phylum mostly contains of
roundworms or worm-like organisms. They
have a digestive, nervous and reproduction
systems, but they lack a circulatory and
respiratory. Nematodes have the ability to
give off carbon dioxide and pick up oxygen
molecules from the moist environment. This
is only possible due to their high surface
area compare to there small body. Just like
the Cnidaria they are able to use their
structure in a moist environment to make
up for their lungs.
Nematode

What Are Nematodes?
Often referred to as roundworms,
nematodes are not closely related to
true worms. They are multicellular
insects with smooth, unsegmented
bodies. The nematode species that feed
on plants are so tiny that you need a
microscope to see them. The adults
often look long and slender, although
some species appear pear-shaped.
These plant parasites are not the same
roundworms as the filarial nematodes
that infect the human body, spread
diseases, and wreak havoc on the
immune system.
Some nematodes feed on the outer
surfaces of a plant while others
burrow into the tissue. Soil-dwelling
nematodes are the most common
culprits, but some species can damage
plant roots, stems, foliage, and
flowers.
No matter where they feed, these tiny
worms can seriously damage to crops
with their sharply pointed mouths by
puncturing cell walls. The real damage
occurs when a nematode injects saliva
into a cell from its mouth and then
sucks out the cell contents. The plant
responds to the parasitic worms with
swelling, distorted growth, and dead
areas. Nematodes can also carry
viruses and bacterial diseases inject
them into plants. The feeding wounds
they make also provide an easy
entrance point for bacteria and fungi.
Beneficial nematodes that enrich the
soil may feed on the decaying
material, insects, or other nematodes.
What Nematodes Look
Like
Unlike most other disease-causing
organisms, plant-parasitic nematodes
seldom produce any characteristic
symptoms. Most of the symptoms that
do appear are vague and often
resemble those caused by other factors
— such as viruses, nutrient
deficiencies, or air pollution.
Nematodes feeding aboveground may
cause twisted and distorted leaves,
stems, and flowers.
Root nodules invaded by
nematodes.
GETTY IMAGES
If nematodes are feeding on the roots,
a plant may look yellowed, wilted, or
stunted and infected food crops will
usually yield poorly. If you suspect
worm injury to roots, carefully lift one
of the infected plants and wash off the
roots for easier inspection. If
nematodes are causing damage, you
may see small galls or lesions, injured
root tips, root rot, or excessive root
branching.
How They Spread
Whether they feed above or below
ground, most nematodes spend at least
part of their life cycle in the soil.
While they can’t move very far under
their own power, they can swim freely
in water and they move more quickly
in moist soil — so it's a good idea to
keep your soil well-drained. They also
spread by anything that can carry
particles of infested soil, including
tools, boots, animals, and infected
plants.
What About Beneficial
Nematodes?
Beneficial nematodes can range from
1/25 inch to several inches long and
have slender, translucent,
unsegmented bodies. Their roles in the
garden vary. Some are soil dwellers
that break down organic matter,
especially in compost piles. You can
easily spot these 1/4-inch-long
decomposers.
These types actually combat a variety
of pest species, including weevils,
clearwing borers, cutworms, sod
webworms, chinch bugs, and white
grubs. Nematodes attack and kill these
insects by either injecting deadly
bacteria or entering the host,
parasitizing, and then feeding on it.
Whenpurchasing and applying them to
your garden, it is very important to
select the right species because
different kinds of nematodes are
effective against different pests. In
addition, nematodes require moist,
humid conditions and fairly warm soil
to do their job well. Water all
application sites before and after
spreading nematodes and follow
application instructions carefully.
Malik
1 month ago
B nematodes
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