Earth science hope it helps
Answer:
Blood clothing is an example of positive feedback.
This type of feedback mechanism is useful to the body because it multiplies the factor that intervenes in clotting accelerating the process.
If a toxin affects the molecules that signal for platelets the feedback will not be effective enough to produce clotting and the body will keep bleeding.
Explanation:
Blood clotting is an example of positive feedback due to the fact that when the vascular endothelium is damaged platelets will go to this area and activate themselves once they are in contact with the collagen fibers of the damaged structure. When the platelets are activated they will release the contents that is stored in their granules. One of the contents is a Gq-linked protein receptor cascade, that will increase the concentration of calcium in the platelets. Calcium activates protein kinase C, which, in turn, activates phospholipase A2 (PLA2). PLA2 will modifies an integrin membrane increasing its affinity to bind fibrinogen. The activated platelets change their shape , and the fibrinogen cross-links with the integrin membrane aiding in the aggregation of adjacent platelets. After this the coagulation cascade takes place. there are two pathways the extrinsic and the extrinsic one.
The extrinsic pathway will be activated due to tissular factor released by the platelets and the intrinsic pathway will be activated due to endothelial collagen. The final product of both pathways is factor x.
Factor x will transform prothrombin into thrombin will activate the conversion of fibrinogen into fibrin. Thrombin will form a net of fibrin that will the clot.
A cascade reaction is useful because every component of the cascade are related making a quick reaction once that one of then is activated and can activate other or more factors.
If a toxin affects the molecules that signals for platelets, platelets will not go to the damaged area and in consequence there will not be thrombin and fibrin to form the clot together with platelets.
This because ice is less dense than water of particular temperature range. Water reaches its maximum density at 4 degrees. Ice is important especially for aquatic life in the polar regions. Polar bears give birth and hunt on sea ice and they need it to travel from one region to another. The ice edge in coastal areas is an important feeding ground for the walrus that uses the ice as diving platforms to feed on clams on the sea floor. Ice algae grow at the porous bottom of sea ice and form the base of the unique marine food web connected to sea ice
<span>The majority of mass of any plant is produced from water from the soil and carbon dioxide with sunlight from the air. 6 CO2 + 6 H2O + sunlight ---> C6H12O6 + 6 O2 ... The gluclose (C6H12O6) is a simple sugar that becomes the biomass of the plant. Other minor contributors to the mass are from fertilizers (mostly N, P, and K) and minerals.</span>
<h2>Question:-</h2><h3> Which structure is found in all animal cells?</h3>
<h2>Answer :- Centrioles </h2>
<h2>Explanation:- </h2>
- They are barrel shaped cell organelles only found in animal cell
- There function is to help in division of cell membrane by forming microtubules which help in division of chromosomes ( spindle fibres)
- They play role in arranging microtubules which act as endoskeleton of the cell
- They also help in formation of cell structure like cilia and filaments
