The concept of the struggle for existence<span> concerns the competition or battle for resources needed to live. It can refer to human society, or to organisms in nature. The concept is ancient, and the term </span>struggle for existence<span> was in use by the end of the 18th century. From the 17th century onwards the concept was associated with a population exceeding resources.
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Answer:
A
Explanation:
Living organisms adapt to their moves and positions in response to the environmental changes for their protection or to their advantage. When an entity reacts to the changes in its surroundings, it is referred to as stimulus while the reaction to the stimulus is referred to as a response. Common stimuli are sound, light, air, heat, smell, taste, water and gravity.
Think of burning your finger of fracturing your bone without any pain sensation. It may certainly sound like a superpower or an ideal situation, however, when it comes to the standpoint of survival, it can be disastrous.
It is a characteristic behaviour of living entities to respond to stimuli with the intervention of the Nervous System. It is an organ system ascribed to send signals from the spinal cord and the brain throughout the body and then back from all the body parts to the brain. Neuron acts as the mediator and is the basic signalling unit of the Nervous system.
Pain is the body’s way of letting us know that something is not right. It can prevent further injuries or push us to seek medical attention. Moreover, all of this is possible because humans can respond and react to stimuli due to control and coordination among the various organs and organ systems.
Control and Coordination in simple multicellular organisms take place through only the Nervous system which coordinates activities of our body. It is the control system for all our actions, thinking, and behaviour.
Answer:
During anaphase 2, the chromosomes' centromeres break, and the spindle fibers pull the chromatids apart. The two split portions of the cells are officially known as "sister chromosomes" at this point.
Explanation:
The role of DNA is to storegenetic information. Thegenetic information is storedin the chemical structure of...DNA is short for deoxyribonucleic acid. DNA is found in the nucleus of the cell.
Human,increase population and Overharvesting