Answer:
295
Explanation:
Antibodies (also known as immunoglobulins) are immune system-related proteins that circulate in the bloodstream in order to recognize pathogenic harmful substances (antigens) and neutralize them. An antibody consists of two immunoglobulin heavy chains and two immunoglobulin light chains. There are two types of immunoglobulin light chains: 1-the kappa (κ) light chain, which is encoded by the immunoglobulin κ locus; and 2-the lambda (λ) light chain, which is encoded by the immunoglobulin λ locus. The immunoglobulin light chain is a multidomain protein composed of two domains: 1- the N-terminal variable (V) domain and 2-the C-terminal constant (C) domain. V(D)J recombination is a type of somatic rearrangement process by which T and B cells can assemble different gene segments, which are referred to as variable (V), diversity (D) and joining (J) gene segments. In the question above the number of possible genomic recombination events between immunoglobulin gene segments can be calculated as >> (5 x 35) + (4 x 30) = 295.
The natural rate of extinction as assumed by science is about 5 species per year. Currently scientists estimate we are losing species at 1000-10000 times that rate, with multiple species disappearing every day. A note on this idea is that the average extinction rate gives an unrealistic depiction of nature when we consider the catastrophic extinction events that ended the dinosaurs and shaped the ice age.
The one that is true about cells is Number two. The cell is the basic unit of a structure and function of life. The cells are what makes us living things. All living things are made up of cells.
