The answer is; producing a unique antibody from all other B cells by genomic rearrangement.
An isolated B cell produces monoclonal antibodies (also called Immunoglobulins). Different B cell types produce different types of antibodies (hence the serum of an animal has polyclonal antibodies). Memory B cells are developed when a particular infection is eradicated by the immune system. These B cells proliferate when the infection returns by producing the same antibodies that were effective against the foreign entity.
Multi cellular organisms are composed of many cells whereas unicellular organisms are composed of single cell. Multicellularity is indeed a progressive attribute of evolution where cells form tissue which forms organ and then organ system and finally an organism. Both multi cellular and unicellular organisms has advantages and disadvantages of their own. One of the main disadvantage of multi cellular organisms is that due to such a complex composition and functioning they require a large amount of energy for their maintenance and survival. Different organs and system require a huge amount of energy when it comes to comparison with unicellular organisms. A large amount of energy is also wasted in all these life processes. Though multi cellular organisms can survive in a variety of environmental conditions but then also their survival is difficult than any unicellular organism.
Uring this period he became acquainted with Osama bin Laden, a wealthy Saudi who had joined the Afghan resistance to the Soviets,
Answer:
A
Explanation:
All living organisms ranging from unicellular prokaryotes to multicellular eukaryotes contain genetic material (DNA). This genetic material is usually found on structures called CHROMOSOMES. Although, the chromosomes are contained in the genome of all living organisms, there are differences.
The genetic material of the bacteria (a typical prokaryote) is a single DNA molecule that makes up its single circular chromosomal material, unlike in eukaryotes that contains double-stranded DNA molecules on linear chromosomes. This single circular chromosome of bacteria is found naked in a region of their cell called NUCLEOID, as they do not possess a membrane-bound nucleus that houses it (a unique characteristics of eukaryotes).
The mitochondrial and Chloroplast DNA mentioned in the other options are all components of eukaryotic cells. Bacteria, as a prokaryote does not contain this organnelles. Hence, they are not single replica.
