Answer i will give which of the following are basic challenges of life for every organism? a. obtaining and using energy b. reproducing c. maintaining structure d. all of the above

D; You could make some argument for A only but for this the best answer would be D

The traits that are challenges of life for all organism is : 

A. Reproducing,

Both male and female seek the partners that potentially provide the best genetics

D. Maintaining structure

That's why we strive to provide necessary nutrition for our body such as protein and calcium

F. Obtaining energy

To do our day to day activities we need calorie consumption

hope this helps

ca has a crystalline lattice with positive ions (since it is a metal, metals are positively charged) and electrons flow freely in its structure since the ca atoms have a large nuclear radius so the electrons are not tightly held, therefore the electrons can flow freely since they are not being highly attracted by the nucleus. moreover, one of the properties of metals are that they are conductors of electricity, thus proving ca is the element.