4 is the answer; the cytotoxic t cell ain't with the bs.
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Warm fronts cause several days of cloudy weather, while cold fronts cause heavy snow in the winter.
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.
The answer is C. Because they do have scales
