Out of the options, "Iron" is the most dense here.
In short, Your Answer would be Option D
Hope this helps!
The number of electrons in the outermost shell of an atom determines its reactivity. Noble gases have low reactivity because they have full electron shells. Halogens are highly reactive because they readily gain an electron to fill their outermost shell
The type of battery is dry cell batteries
Generally speaking, acidic soil, with a pH lower than 6.0, yields blue or lavender-blue hydrangea blooms. Alkaline soil, with a pH above 7.0, promotes pinks and reds. With a pH between 6 and 7, the blooms turn purple or bluish-pink. To lower your pH, add garden sulfur or aluminum sulfate to your soil.
The secret's in the soil
Let’s look at why pH is so important.
Most major plant nutrients are more accessible at a pH of 6 to 6.5. A pH that is too high or too low can keep plants from absorbing nutrients from the soil. The nutrients are unavailable — or not absorbable — to the plant because of soil's chemistry. This problem can manifest itself in a variety of ways, but in the case of hydrangeas, the bloom color changes.
Color variation in hydrangeas is due to the presence or absence of aluminum compounds in the flowers. If aluminum is present, the color is blue. If it is present in small quantities, the color is variable between pink and blue. If aluminum is absent, the flowers are pink.
