The expected remaining lifespan of the sun is thought to be about how many years?
a) 7 million years
b)7 billion years
c)77 million years
d)77 billion years

b) 7 billion years

Explanation:

Hi, the sun, like all stars, has a lifespan, characterized by a formation, main sequence, and eventual death

This lifespan began roughly 4.6 billion years ago, and will continue for about another 7 billion years, when it will deplete its supply of hydrogen, helium, and collapse into a white dwarf.

So, the Sun is about half way through the most stable part of its life.

answer: a. a gene that causes a specific trait.

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.