Hi there!
A prezygotic isolating mechanism is a mechanism that causes something to happen, not allowing the organisms to breed before fertilization. I'll explain each one for you.
A - That is postzygotic because the organisms were not stopped before fertilization. The result is a sterile organism.
B - Again, that is postzygotic because the organism was produced.
C - This is prezygotic! The sperm dying shows that something is in action to prevent fertilization, meaning that it cannot happen.
D - Fertilization was successful, so it is postzygotic.
ANSWER:
C - the sperm dies when it reaches the female tract
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Hope this helps!! :)
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The asthenosphere lies 80-200km below the surface under the lithosphere. Convection also occurs in the asthenosphere. The asthenosphere is mostly made of up rock material (magnesium and iron silicates). The asthenosphere makes up 6% of the mantle and lets the lithosphere move.
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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.
Learn more about Hydra here brainly.com/question/1808325
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Answer:
Behavioral responses in organisms require communication between an organism and its environment (option C).
Explanation:
The behavior of an organism depends on the function of relationship with the environment that surrounds it, and the way to respond to the diverse stimuli that are in this environment.
Behavioral responses always occur as a result of the interaction between the physical environment and other living organisms. This interaction triggers a series of stimuli that are perceived by the senses and processed by each organism, developing an appropriate response to each of them.
