If in an eight-cell embryo of an organism, the cells of the upper tier are aligned over the cells of the lower tier at a slight angle, it is likely that the organism is a vertebrate.
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Answer:
The correct answer is convergent evolution.
Explanation:
The wings of bats, butterflies, and most birds are the example of analogous structure. Analogous structures are the structures which are similar in appearance and function but have separate evolutionary origin.
They are similar superficially because they experienced a natural selection that evolved them to have that shape which helps them to fly. Analogous structures are produced due to convergent evolution.
Convergent evolution describes the presence of the same trait in unrelated species. Therefore the correct answer is convergent evolution.
The responsibilities of a scientists is ti discover new possibilities of the future and our world.<span />
Answer:
That is administered and controlled
Step-by-step explanation:
A variable is the condition or a product that may vary without the influence of any investigator. Such variables can be found abundantly in our daily lives, ranging from air to sunlight. Controlling such variables ensures the limitation of their influence on the outcome of an experiment. In connection to this experiment, the variables that are controlled are the mineral content in the water, the amount of bacteria food, the amount of light and the the constant temperature of 20 degrees C.
If not administered or these variables controlled, the experiment would not clearly explain the impact of caffeine on the heart beat of the water fleas as other variables may have influenced it. Thus variables are controlled to study the singular impact of any agent or effect.
