During the S phase in the cell cycle, the chromosomes are replicated so that there are two copies. These copies are necessary so that each daughter cell created during the M phase will have an identical copy of the DNA.
Therefore, the answer is A: The DNA must be replicated.
The chromosomes joining, cell membrane expanding, and cytoplasm separating all happen during the M phase (mitosis).
Water can act as either a base or an acid. Water acts as an acid by donating a hydrogen ion when it reacts with a stronger base such as sodium hydroxide. Water may also act as a base when it accepts hydrogen ion when reacting with a strong acid such as hydrochloric acid. This is based on Bronsted concept and definition of a base ( proton acceptor) and acid (proton donor). Such a compound that can act as a base and as an acid is called an amphiprotic molecule.
Octopus and squid have chemoreceptors on their tentacles. The correct option is the third option.
