Positive affect" refers to one’s propensity to experience positive emotions and interact with others and with life’s challenges in a positive way. Conversely, "negative affect" involves experiencing the world in a more negative way, feeling negative emotions and more negativity in relationships and surroundings.
These two states are independent of one another, though related; someone can be high in positive and negative affect, high in just one, or low in both. Both states affect our lives in many ways, particularly when it comes to stress and how we handle it.
Natural selection occurs when one allele (or combination of alleles of different genes) makes an organism more or less fit, that it is able to survive and reproduce in a given environment. If an allele reduces fitness, its frequency will tend to drop from one generation to the next.
i believe that the cell will expand because there is less sugar in the water. if you were to add more sugar into the water, then the cell will shrink in size because sugar and salt is the same thing if you add it in water.