In a hydra, digestion is completed intracellularly.
Hence option (a) is correct.
Small, freshwater organisms of the phylum Cnidaria and class Hydrozoa are grouped under the genus Hydra. They are indigenous to temperate and tropical climates.
The digestion takes place intracellularly in Hydra.
Because of their ability to regenerate and the fact that they don't appear to age or experience old age, hydra have drawn the attention of biologists.
Like most other cnidarians, hydras have a pretty straightforward digestive system.
They have a two-way digestive system, which differs from mammals in that food and waste enter and exit through the same aperture. A "blind gut" is the name for this configuration.
The center of the hydra's body is occupied by its digestive tract.
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Crayfish are invertebrates which means they don't have a backbone. They are also arthropods, which means that they have a protective exoskeleton on the outside of their body. Other arthropods include insects, spiders, and centipedes. Crayfish continually shed their exoskeleton and regrow a new one. During this transition is when they are most vulnerable to predators because they aren't protected by their outer shell.
Crayfish are found all over the world in many different freshwater environments, such as rivers, creeks, springs, and swamps. But this doesn't necessarily mean that you will be able to find them. They are somewhat cryptic because they dig out homes for themselves under rocks and blend in well with their environment. Crayfish will ardently defend this dwelling against intruders using their strong front claws
C.) 45 AND 75............
There are man chemical and physical changes such as geno and pheno.
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