I recommend reading about "Survival of Fittest" and "Natural Selection" to answer your question.
The answer to this question is VERY big. Well, if you want the simplest answer, diversity and selection of good traits within the population.
A trait that is beneficial to survival.
adaptation
cause they do
A beneficial feature that helps survival is the ability to find food and water. Without these basic necessities, it is impossible for plants, animals, or even humans to survive.
The behavior of an organism is influenced by both its heredity and its environment.
A trait that is beneficial to survival.
Scientists have shown that beneficial mutations do occur to produce brand new alleles(variants of genes) that improve an organism's chances of survival in a particular environment
Those that increase your health, your survival, your ability to have children and of course too many other benefits to name, here. Generally mutations are the key to natural selection. Beneficial mutations that occur allow an organism to survive longer, thus reproduce more, passing this mutated trait down to their offspring.
Desirable features mean features that are beneficial to the organism. That is, an organisim with these features has a higher chance of survival as it is better adapted to it's environment.
As with any organism, that organism has to be important to itself to ensure survival.
adaptation
A trait that is beneficial to survival.
A trait that is beneficial to survival.
Interdependcy is when an organism depend on another organism for survival
Non living factors that affect organism survival are called abiotic factors. Living factors that affect organism survival are called biotic factors.
Reproduction
The process of evolution tends to produce organisms whose genes contribute to the survival of the organism. If an organism has genes which impede or prevent survival, then the organism is less likely to survive. A species with such genetics would die out.