All organisms are grouped into five kingdoms. Those are Monera, Protoctista, Fungi, Plantae and Animalia. The division is made based on 3 criteria. Those are cellular organization, arrangement of cells, and type of nutrition. Cellular organization is whether they are eukaryotic or prokaryotic. Cell arrangement is whether they are unicellular, multicellular, with or without true tissue differentiation etc. Type of nutrition is whether they are autotrophic or heterotrophic. Kingdom Protoctista includes algae, protozoans, oomycota and slime moulds.
Answer:d) contracting her pupils and increasing secretion of stress hormones.
Explanation:
Peripheral nervous system consists of 3 major neuronal levels: vegetative (reticular formation and brain stem), limbic system and neocortical level. The RAS is the link between the brain and the spinal cord.
Brain stem consists of pons, medulla oblongata and mesencephalon. Brain stem is responsible for involuntary functions such as heart beat, respiration and vasomotor activity. Limbic system represents the emotional control center. It consists of thalamus, hypothalamus and pituitary gland and maintains homeostasis. Neocortical part processes sensory information and regulates emotional responses.
Autonomic nervous system (ANS) regulates visceral activities and organs (circulation, digestion, respiration and temperature). ANS has two divisions: sympathetic and parasympathetic nervous system.Parasympathetic nervous system regulates homeostasis via the release of acetylcholine (Ach). Parasympathetic nervous system is responsible for energy conservation and relaxation.
There are three stages in the stress response: immediate effects of stress, intermediate effects of stress and prolonged effects of stress.
Scientists often experiment with Brassica plants because they have a relatively short growth period, and they may represent model organisms for genetic studies.
<h3>Why use the Brassica plants in genetic studies?</h3>
Brassica plants are considered model organisms in genetic studies because they have a short period of growth (around 30 days), which allows the analysis of a high number of generations in less time.
Moreover, the genome of Brassica plants contains 24 Gigabases (24 billion nucleotide bases), which is a high number to be considered a model organism in genetic studies.
In conclusion, scientists often experiment with Brassica plants because they have a relatively short growth period, and they may represent model organisms for genetic studies.
Learn more about genetic model organisms here:
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