Question

Which was the last human chromosome to be completely sequenced?
(a) Chromosome 1
(b) Chromosome 11
(c) Chromosome 21
(d) Chromosome X

Answer 1

Chromosomes are thread-like structures that are a part of the genetic material of an organism and is a long DNA molecule that is present in most eukaryotic organisms that include the packaging of proteins which are known as histones.

Complete answer:
Chromosome 1 was the last human chromosome to be completely sequenced and was completed in May 2006. it was the last human chromosome among the 24 chromosomes and 22 autosomes and X and Y to be sequenced. Chromosome 1 is the largest human chromosome which consists of copies of chromosome 1 in humans and has nucleotides base pairs that are the basic units of information for the DNA. Chromosome 1 can cause several diseases: hearing loss, glaucoma, breast cancer and Alzheimer's disease. It is a sequence that reveals signals of the selection in specific genes that contribute towards human fitness.

Additional information:
Chromosome 11 : Chromosome 11 is among the 23 pairs of chromosomes in humans and is present in humans with two copies of it. It consists of about one thirty-five million base pairs that represent about $5\%$ of the total DNA in the cells. The short arm is termed as 11p and the longer arm is termed as 11q. chromosome 11 can cause several diseases which include autism, albinism, bladder cancer, breast cancer and others.
Chromosome 21 : Chromosome 21 is present in humans and is the smallest human autosome and chromosome which consists of 48 million base pairs and is represented as two per cent of the total DNA in the cells. The trisomy of chromosome number 21 is known as down syndrome and it is the second human chromosome that is fully sequenced.
Chromosome X : Chromosome X is the sex chromosome that is present in many organisms that include mammals and is found in both males and females. It consists of 53 million base pairs which include 800 protein-coding genes.

So, the correct answer is 'Chromosome 1'.

Note:
Chromosomes in bacteria are circular and not all organisms consist of chromosomes. The chromosomes are responsible for the gender of the foetus. The X chromosome is in more abundance in the males and there are two types of chromosome mutations.