The concentration of calcium in a cell is 0.3%. The concentration of calcium in the surrounding fluid is 0.1%. How could the cell obtain more calcium?

Primary active transport                                                                                              

Explanation:

In a cell, the movement of molecules like calcium ions (Ca²⁺), to a region having high solute concentration from a region having low solute concentration, through the cell membrane requires metabolic energy and is known as Primary active transport.

It is given that the concentration of calcium in the cell (0.3%) is greater than the concentration of calcium in the fluid surrounding the cell (0.1%). So the calcium ions move into the cell and the cell obtains more calcium.

Therefore, the cell obtains more calcium by the process of Primary active transport.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.