Answer:
Evolution is driven by rare mutations that occur in the DNA of organisms. These mutations could be lethal, neutral and some advantageous. The lethal mutations cannot exist in a population because the offspring is unable to survive to term in pregnancy or dies just after birth. The neutral are ones that do not considerably affect the organisms – though they could result in a disadvantage. The beneficial ones are the one that is kept in the population by natural selection because they confer an advantage e.g in the fight for resources or escaping predation and etcetera. Therefore, it's like a game of chances by nature. Paleontologists discover many species of organisms some of which are imperfect because nature produced them but they died off because their mutations gave them a disadvantage against better-adapted individuals.
The <em>Tiktaalik</em> fish from 375 million years ago became extinct because it did not well-developed eardrum for detecting vibrations in water which is significant in survival.
Dinosaurs during development of feathers had many imperfect species before the right wings for flight were conjured up by nature. An imperfect species is the <u><em>Tianyulong confucius</em></u> had stiff feathers that lacked vanes hence were not ideal for flight
Translation<span>. The mRNA formed </span>in transcription<span> is transported out of the nucleus, into the cytoplasm, to the ribosome (the cell's protein synthesis factory). Here, it directs protein synthesis. Messenger </span>RNA<span> is not directly </span>involved in<span> protein synthesis − transfer </span>RNA<span> (</span>tRNA<span>) is required for this.</span>
It flows through the consumers (first level second level so forth). However, at each level, it loses 90 percent of the energy as heat. So at each level, each consumer will only get 10 percent of the energy.
Answer:
This question lacks options, options are:
A.They maintain the cell’s shape.
B.They regulate cell processes.
C.They protect the body from infectious agents.
D.They signal the immune system to destroy pathogens.
E.They speed up biochemical reactions.
F.They send electrical signals.
The correct answers are C and D.
Explanation:
B cells and T cells use different biological weapons to attack the pathogen. The first secrete proteins called antibodies, which are distributed via the blood or the exposed surfaces to the environment, such as mucous. Antibodies are glycoproteins that circulate in the bloodstream looking for antigens that cause some type of damage to the body. Antibodies recognize and neutralize pathogens in a highly efficient way. Once the antibodies are produced, they remain circulating in the bloodstream for several months, which generates immunity for a long period of time to a certain antigen, in other words, they are capable of recognizing other molecules (antigens) in a very specific way and forming stable complexes with them (immune complexes). Its appearance in plasma is part of the adaptive immune response, in what is known as a specific humoral response, constituting a very effective defense against pathogens.
