When Sarah performed this experiment, she changed the levels of nitrogen in order to observe the changes in the morphological features of the plant.
All of the characteristics of the plant that she observed were dependent on multiple different things, but the level of nitrogen was an independent variable that she was changing at her will.
Answer : Option B) Swifts earlier attempts at nonsatirical essays and speeches had failed to elicit a response from the government.
Explanation : Jonathan Swift chose a satirical essay to address the issues of Ireland's poor in A Modest Proposal as his previous attempts to get a response from the government was failed and not fruitful. He thought of approaching in a satirical way so that he can pin-point the issues to the government in humorous way.
<span>The correct option from the given options is: "Scientist have determined the composition of Earth's core by using radiometric dating to examine meteorites".
</span><span>To date materials the procedure of radiometric dating or
radioactive dating is used, for example, rocks or carbon, in which trace
radioactive impurities were specifically fused when they were framed. The
strategy looks at the abundance of a normally happening radioactive isotope
inside the material to the abundance of its decay items, which shape at a known
consistent rate of decay.</span>
