Our skin cells divide rapidly in order to maintain a protective barrier against infection.The outer skin layer is called the epidermis and contains mostly dead cells that contain keratin.Keratin is a tough fibrous protein found in hair,skin and calluses and acts as a protective coating.The epidermis cells are constantly undergoing mitosis so the outer dead cells containing keratin are rapidly replaced as they fall off, which occurs after so many days.Then the newer living cells start producing keratin,lose their cellular contents,then die and the cycle goes on.The skin acts as a barrier to infection,therefore,it's constantly renewed and repaired.
Answer:
B. decreases salivation and increases blood pressure
Explanation:
The sympathetic nervous system is part of the autonomous nervous system which controls involuntary responses of the body such as salivation and blood pressure.
The sympathetic nervous system is majorly responsible for body actions that are produced when threat is perceived. It generates responses referred to as the “fight or flight” response. Examples of such responses include, increased breathing, increased high blood pressure, dilation, decreased salivation, etc.
Activation of the sympathetic nervous system would result in rise in the blood pressure as can be witnessed by someone whose body has perceived a threat or reacting to a stressful situation.
The control of salivary production by the sympathetic nervous system leads to the release of noradrenaline which acts on certain receptors that results in decrease in the production of saliva. This is evident in a person that is facing a threat also.
large surface area,
high CO2 concentration
High blood diffusion (from high to low concentration)
Thin walls adjusted for gaseous exchange.
Answer:
Yes, plants respire all the time. It occurs in the mitochondria of a plant cell.
Answer
Inputs: light, water and carbon dioxide
Outputs: glucose and oxygen
Explanation
Photosynthesis is a process in which leaves absorbs sunlight energy, uses water and carbon dioxide is fixed to give two output products glucose or carbohydrate which is used as a fuel by the plant and oxygen which is released as a by-product of photosynthesis
