The surfaces of leaves contain guard cells that open and close the stomata. What is the primary function of the guard cells?

They control the loss of heat produced by the plant.

They control the loss of water through transpiration.

They control the loss of carbon dioxide used during respiration.

They control the loss of sugars produced during photosynthesis

B.

Explanation:

They control the loss of water through transpiration

Explanation:

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.