We can predict or comment about reactivity of elements by taking into consideration their electronic configuration that imparts stability or un-stability to an atom.
Explanation:
Reactivity : It refers to the affinity of a substance to combine with other substance .
Elements are mainly of two types :
Metals and Non metals
In terms of metals or non metals it can be defined as tendency to loose or gain electrons .
On the basis of it ,we can easily make out or comment about the reactivity of element (metal or non metal ) .Like ,if an element has completely filled outermost shell or we can say have stable electronic configuration then it is already stable .Therefore , it won't react with any other element .
But, if its outer shell isn't complete then in order to attain stability it will combine or react with other .Hence , we can say it will be quite reactive .
The answer is C. Pheromones are hormones (which are proteinous) produces by individuals of the same species and are a means to send communication signals for social interactions. They signal alarm, food and even sex. Sex pheromones are released by females beetles into the environment to signal their availability for mating. The pheromones are picked up by receptors on the male beetles and this is how they find the females.
I believe the answer is head-on and port (left). The side lights are usually visible to vessels approaching from the front or the side. The red light usually indicates a vessel's port (left) side while the green light indicates a vessel's starboard (right) side. These lights ensure that there is safety at night as the vessels navigate.
