The Cross-Linkage Theory or also referred to as the glycosylation theory of aging was discovered or proposed by Johan Bjorksten in the 1940s. According to this theory, the aggregation of cross-linked proteins can damage cells and tissues this slowing down the bodily processes that eventually results to aging. In recent studies, cross-linking is associated with age-related changes in the studied proteins. Furthermore, this theory stresses out that the binding of glucose to proteins can cause various problems. Once the said binding occurs, the protein becomes impaired which leads to its performance inefficiency. Living a longer life would also mean increasing the possibility of oxygen-glucose meeting and protein. Some of the known cross-linking disorders include senile cataract and the appearance of tough, leathery, yellow skin.
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Answer</h2>
Stimulus ➡ Touch Receptor ➡ Sensory Nerve cell ➡ Relay nerve cell ➡ Muscle ➡Response
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Explanation</h2>
- When a body touches a hot or very cold body, a stimulus is generated.
- Touch receptors convert this stimulus into a nerve impulse and transmit it to the sensory neurons located in the spinal cord (CNS) via peripheral nerves.
- The impulse travels across a synapse to relay neurons
- Relay neuron passes impulse across the second synapse to motor neurons.
- Now impulse travels along motor neuron to reach the effector (muscle)
- Muscle contract and hand is withdrawn quickly (Response)
According to the research, the correct option is A, population genetics is the study of how allele frequencies in a population change over time.
<h3>What is population genetics?</h3>
It studies the origin, amount and distribution of genetic variability present in populations.
It explains the variation between individuals, as well as the dynamics of alleles and genotypes within and between populations.
Therefore, we can conclude that according to the research, the correct option is A, population genetics is the study of how allele frequencies in a population change over time.
Learn more about population genetics here: brainly.com/question/13049509
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