Answer:
C. At least five mass-extinction events have occurred during the last 500 million years.
Explanation:
- The history of mass extinct is related to the five mass extinctions that are caused over by the 350 million years n which many species have disappeared in there short geologic time.
- A massive extinction is caused in the Permian Triassic extinction event i.e about 250 mn years ago which on an estimate has killed 90% of the species.
- The Cretaceous–Paleogene extinction event that occurred over 66 million years ago is known to have wiped out the dinosaurs and many other species.
Answer:
When the frequency of stimulation of a muscle increases -without it having the opportunity to relax- a process called summation (addition) occurs, promoting an increase in the generation of force in the isolated skeletal muscle.
Explanation:
Summation is a phenomenon that occurs as a consequence of the arrival of successive stimuli that produce the contraction of the skeletal muscle before it achieves its partial or total relaxation, between subsequent stimuli.
<em>When the summation occurs in the muscle, the force generated on it increases its magnitude proportionally to the number of stimuli received, maintaining the muscle contraction in time</em>.
Tetany is the prolonged contraction of a muscle in an abnormal way, by the summation of stimuli received , as some bacterial toxins can produce. The summation can be temporary -when multiple stimuli reach the muscle in a determined time- or spatial, when the amount of stimuli activates a greater amount of motor units.
Learn more:
Spatial summation in a post synaptic neuron brainly.com/question/9632682
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.
Hi these proteins are called *Cyclins *
Hope this helps you please help me by saying thanks.
Hi the rectal route is preferred over the oral route because- rectal medications are usually not subject to first pass metabolism.
Hope this helps.
Please help me by saying thanks and rate the brainiest answer. Thank you.
