This is called 'controlled' or 'prescribed' burning. Usually fires in the environment are regarded as undesirable and dangerous, but fires actually fulfil an important ecological role, and animals and plants had adapted to a certain frequency and intensity of fires. The seeds of some trees or grasses germinate after forest or grass fires, as the more open conditions after a fire allows the seedlings to compete and avoid being shaded and smothered by more established trees. Unfortunately, farming and forestry practices have in many cases resulted in a reduction of fires. A reduction in the frequency of fires also allows the build up of dead wood, and when a wild fire does occur, the amount of available fuel results in very hot, large and damaging fires. Therefore, management of forests and other environments such as prairies often use controlled burns to avoid the buildup of dead organic mass and to replicate the natural fire cycle.
A is correct: mononucleosis, also known as mono, can be contracted by sharing water bottles since it is spread by saliva. Hope this helps! :)
<h2>Functions of spleen</h2>
Explanation:
The major functions of spleen besides filtering the blood of foreign materials and phagocytosis of old defective erythrocytes are:
- Initiate immune responses against infections by liberation of antigen and activation of lymphocytes (T and B cells)
- Secretes bactericidal agents which act against invading bacteria
- Secretes interleukins which promote the growth of lymphocytes or antibodies that act against pathogens
- Reservoir: Pools blood by storing thrombocytes, immature erythrocytes.
- Hematopoiesis: Blood cells like erythrocytes, lymphocytes and monocytes develop and mature in spleen especially during the early fetal life.
Xray diffraction images produced by Franklin showed that DNA is a double helix.