Question

Which of the following must be true to consider something to be alive?
1. It must be able to replicate its DNA.
2. It must be able to respond to light.
3.It must be able to convert energy from one form to another.
4.It must be able to move.

Answer 1

One of the most important things that characterize a living organism is its ability to replicate the DNA.

DNA replication does not take place in dead organisms.

Dead organisms respond to light in many ways, they may gain or lose mass and certainly convert from one type of energy to another.

Answer 2

The correct option is (1)

It must be able to replicate its DNA.


⏩Before a cell divides, its DNA  is replicated (duplicated.) Because the two strands of a DNA molecule have complementary base pairs, the nucleotide sequence of each strand automatically supplies the information needed to produce its partner.

⏩DNA replication begins with the "unzipping" of the parent molecule as the hydrogen bonds between the base pairs are broken. Once exposed, the sequence of bases on each of the separated strands serves as a template to guide the insertion of a complementary set of bases on the strand being synthesized.