Single celled organisms are able to maintain homeostasis, withstanding relatively large alterations in their external environments . This is due to the fact that they posses structures that regulate and carry out life functions. They perform all the functions that are necessary for an organism to exist.
The ability to obtain all the substances that are essential for their existence eliminates the need for dependence on other cells. These single-celled organisms are thus able to maintain a relative state of equilibrium within their internal environment.
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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Well, biotic factors are living things in an ecosystem such as animals or insects. Abiotic factors are non living things in an ecosystem such as sunlight or temperature. I would say biotic factors would be more harmful since this includes bacteria or other diseases, not many abiotic factors would pose a great threat to the entire human species. Hope this helped.
Answer:
monohybrid cross
Explanation:
An experiment during which two heterozygous F1 individuals are bred and produce two different phenotypes for a single trait is termed a monohybrid cross.