II. Completați frazele următoare utilizând termenii științifici corecți: a) Celula cu nucleu individualizat și organite celulare se numește ………… .
b) ADN-ul și ARN-ul se numesc ………… .
c) ………… ………… sunt structuri care funcționează ca niște organe miniaturale, fiind răspunzătoare de îndeplinirea unor anumite funcții.
d) Nucleoidul este ………… al procariotelor.
e) Toate celulele prezintă ………… în timp ce peretele celular e prezent la celulele ………… .

4

water is a polar molecule. a chemical bond is a force of attraction between atoms or ions. bonds form when atoms share or transfer valence electrons. atoms form chemical bonds to achieve a full outer energy level, which is the most stable arrangement of electrons. so, false

explanation:

in h2o molecule, two water molecules are bonded by a hydrogen bond but the bond between two h - o bonds within a water molecule are covalent. the greater the electronegativity difference, the more ionic the bond is. bonds that are partly ionic are called polar covalent bonds. nonpolar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal.

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds