If a pea plant has a tall stem, what possible combinations of alleles could it have?

controls stem height in peas, for example, has one allele for tall stems and one allele for short stems. Each pea plant inherits a combination of two alleles from its parents either two alleles for tall stems, two alleles for short stems, or one of each. Individual alleles control the inheritance of traits

Explanation:

a polar bond is formed when electrons are shared unevenly between atoms

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.

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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.