Which one of the following is a difference between a normal cell and a cancer cell?
a.

normal cells undergo apoptosis while cancer cells don’t.

b.
normal cells do not respond to regulatory signals while cancer cells do.

c.
normal cells invade surrounding tissues while cancer cells don’t.
which of the following checkpoints determines if dna replication was successful?
a. g2
b. g1
c. m

it would lead to upper respiratory infections and pneumonia.

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.