B. Idioms should not be taken literally and must be understood as a whole.
For example: it's raining cats and dogs.
It's not really raining cats and dogs - you need to know this idiom in order to understand that it means there are some heavy rains outside.
<u>Answer</u>: B: the sequence of nucleotides in the DNA
<u>Explanation</u>:
Although there are only four nucleotides composing all DNA on Earth, the different order in which they are arranged will specify for different genes. The number of these genes and which of them are active, is what makes individuals unique.
<span>As cells develop some genes are turned off permanently </span>
Answer: Gravitational lensing
Explanation: The arc that was seen around the galaxy by the scientist was caused by gravitational lensing; this is when a light dip and curves in the presence of huge objects.
Gravitational lensing can be simply refered to as a phenomenon where a gravitational field is created by a huge matter (cluster of galaxies) in space which distort and magnifies the lights coming from another huge matter (cluster of galaxies) from a distance but on thesame line of sight. (causing a formation of arcs of light around the huge object).