N the brain<span>, dopamine functions as a </span>neurotransmitter<span>—a chemical released by </span>neurons<span> (nerve cells) to send signals to other nerve cells. The brain includes several distinct </span>dopamine pathways<span>, one of which plays a major role in </span>reward-motivated behavior<span>. Most types of rewards increase the level of dopamine in the brain, and many </span>addictive<span> drugs increase dopamine neuronal activity. Other brain dopamine pathways are involved in </span>motor control<span> and in controlling the release of various hormones. These pathways and </span>cell groups<span> form a dopamine system which is </span>neuromodulatory<span>.</span>
Answer:
Arthropods have a tough, non-living outer shell called exoskeleton, which protect their soft bodies while echinoderms have living endoskeletons, which develops within the deeper skin or body tissues and act as their protective covering.Explanation:
Because humans can not stay the same forever
Siliceous ooze is mostly composed of the shells of diatoms (single-celled algae) and radiolarians (single-celled animals)
Answer: B).
In exponential growth, the growth rate of population per capita remains the same in spite of the size of the population, thus, resulting in the population to grow faster and faster as it gets bigger. However, in nature, the populations may grow exponentially for certain time duration, and they eventually get restricted due to limited availability of resources.
In the graph, it is evident that from 1950 to 1990 there is exponential growth, signifying that the fish exhibited almost optimal conditions of living. However, in 1990 the population started to decline steadily, demonstrating an extreme lack of resources or enhancement in predatory species.
