The first line of defense is the skin. It is the largest organ in the body and it acts as a barrier between invaders (pathogens) and the body. Microorganisms and bacteria cannot enter the skin unless it is broken. Inflammation is one of the signs that the first barrier has been destroyed.
The second line of defense is your cells. These are your white blood cells (leukocytes). There are different types but each one fights off the pathogens in order to protect you.
Once the bacteria has taken over what happens is that your white blood cells will increase and will activate your lymphatic system. This explains why you get high fever and the lymph nodules are swollen when one is sick. For instance, tonsils will inflame for those who have bacterial infection in the throat. <span />
Answer:
Crossing over is a process in which exchange of segments occur between two non sister chromatids.
Explanation:
Crossing over is a process in which two non-sister chromatids of homologous chromosomes exchange the segments of genetic material with each other during meiosis. Due to this process, variation occurs in an organism.
Independent assortment is a process in which different alleles are sorted to different gametes which occurs independently and does not effect one another. This process occurs in metaphase of meiosis l.
Joining of sex cells is a process in which sex cells of male and female join together formed a zygote which turn into a new organism. These sex cells are formed during meiosis which are haploid in nature.
Mutation and crossing over are the factors that cause inherited genetic variations within populations.
Sudden change occurs in the genes of an organism due to the exposure of the cell to radiation or chemicals.
Each organism corresponds with one another because one organism feeds on another and so on and so forth
Answer and Explanation:
Observing population directly gives you accurate result .
Direct observation does not need any intermediary as they themselves go for survey.
So, it is cost efficient.
Whereas indirect observing may involve manipulations.
It requires someone or many to hire who helps in surveying.
It incurs cost.
Thus, direct observation is always better than indirect observation.
