It is OH- (hydroxide ion)
Elements Y and elements Z would have similar properties due to the fact that they both posses the same number of valence electrons. They both have a single valence electron that determines the corresponding elements bonding properties and the fact that it can either donate 1 valence electron to produce an ion that would be attracted to another atom, that is also an ion. Assuming that these elements are group 1 elements, they do not undergo in covalent bonding.
Answer:
Dependent variable
Explanation:
In every experiment, there must be a dependent variable and an independent variable.
The independent variable is that variable that you have to manipulate in order to receive a response. E.g, in the experiment described in the question, the amount of sunlight a sunflower plant receives is the independent variable.
The dependent variable is the number of seeds produced. It is the response obtained by carefully manipulating the amount of sunlight

The correct choice is ~ A
S.I unit of time is <u>Second</u>