Because you will focus past ("overshoot") your specimen. (Like using a race car as a shopping cart: it's too fast, and you'll fly past the cereal and never even see it before you realize you need to stop.) Also: you risk crushing the slide and objective against each other (on older or cheaper scopes), and that would be a costly (and embarrassing) mistake.
In general, the process responsible for the growth and repair of human tissue is the healing process, which takes place in three phases.
1. inflammatory response. Injured tissues release chemicals that draw resources to the area, alert the body that damage has occurred and inhibit function to prevent further injury.
2. Repair phase. Once injured area is walled off and debris removed, construction to replace or repair injured tissue begins. New blood vessels grow in the injured area maximizing transport within tissue.
3. Remodeling phase. Construction of permanent tissue , typically strong scar tissue made from dense network of collagen fibers.
Looking at it from cell level, the process of mitosis is actually taking place during healing.
Mitosis is used for growth and repair and produces diploid cells identical to each other and to the parent cell.
New cells are needed throughout life. These are for growth and replacement of damaged or worn out tissue. The body obtains such through the process of mitosis.
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- The environment needs to change in order to natural selection to occur.
Reason:
Because, Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations.
2. Population has some genetic variations.
Reason:
Genetic variation is essential for natural selection because natural selection can only increase or decrease frequency of alleles that already exist in the population. Genetic variation is caused by:
mutation and random mating between organisms
3. Nature select organism with specific traits to survive and reproduce.
Reason:
According to Charles Darwin's theory of evolution by natural selection, organisms that possess heritable traits that enable them to better adapt to their environment compared with other members of their species will be more likely to survive, reproduce, and pass more of their genes on to the next generation.
Hydrogen as in hydrocarbons
nitrogen as in cyanides
sulphur as in carbon di sulphides
oxygen as in combustion of carbon
the rest i left out needs a third party element to bond to carbon