Helloooo
how are you today?
I want to say individuals more so than entire populations. That being said it's because the entire populations of living things are able to evolve and move forward through slow evolution.
I believe it is natural selection. Natural selection is when over a period of time, traits that are formed to help the organism survive, are passed to the next generation. For example, if there were two types of rabbits. One had black fur and the other was white. They both lived in the artic. The black furred rabbits are mostly eaten by predators because their black fur is easily seen against the ice and snow. Over a period of time, the black furred rabbit would die out. The next generation would mostly have white fur to help them survive.
Traditionally the unit was the kilo-calorie but commonly just referred to as calorie. today's SI unit is the Joule...
Abiotic Factors of Taiga Biome: The abiotic factors includes temperature, sunlight, soil, air, water. In taiga biome the climate is marked by bitterly cold winter of long duration and cool brief summer season. The winter months are always below freezing point.