Im gonna guess the answer is false but I might be wrong
Complete question:
Which of the following pairs represent homologous structures?
- Wings of grasshopper and forelimbs of flying squirrel
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Tentacles of Hydra and arms of starfish
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Forelimbs of a bat and forelegs of a horse
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Wings of a bird and wings of a moth
Answer:
3. Forelimbs of a bat and forelegs of a horse
Explanation:
Homologous characters are structures with the same basic elements. Their position in the body and the relations with adjacent structures are also the same in different organisms, and they even share the same embryological development.
These structures might show variations between the organisms exhibiting them. Variations might be related to their function and to the environment in which the organism lives. The function they accomplish is not necessarily the same in all the organisms involved.
These homologous characters are present in organisms related that share a common ancestor.
For example, whales, humans, and cats all have the same bones in the same order, but they matured differently in later embryological development.
Among the options, the only possible pair that represents homologous characters is option <em>3. Forelimbs of a bat and forelegs of a horse</em>. Both structures are the anterior extremities of the animals and share the same bones, even though they might differ in the development degree. Forelimbs and forelegs have the same position and relation with other structures in the body, and embryologically, they are the same.
Answer:
Scientists believe that the different types we know emerged as early humans adapted to infectious diseases.
Explanation:
Different human blood types probably emerged to ward off infectious diseases. The incompatibility of some blood types, however, is only an "accident" of evolution. But this is a relatively recent problem, since blood transfusion has been around for only a few hundred years.
There are four main blood types. The oldest is B, which must have originated about 3.5 million years ago - it existed even before the human species evolved from its hominid ancestors, from a genetic mutation that modified one of the sugars in the surface of red blood cells.
Approximately 2.5 million years ago, mutations inactivated sugar, resulting in type O blood, which has neither type A nor B. sugar. AB blood, as it is easy to suppose, is covered by both sugar A and sugar by B.
B. they are defined by their biotic factors and abiotic factors.
