. One function of the circulatory system is to help maintain a uniform body temperature. Explain how the constant circulation of blood through the body can accomplish this.

Capillaries are the blood vessels with the smallest diameter and those closest to the surface of the skin. The blood that circulates through them is therefore closer to the outside air than the blood in the rest of our blood vessels. As the capillary dilates, a greater amount of blood is exposed to the air, which allows it to cool down and our body temperature to be maintained.

Explanation:

Blood is a solution where solutes and cells are found and that participates in homeostatic mechanisms such as the control of body temperature, helping to regulate respectively the preservation and elimination of heat. Blood vessels are the routes of the cardiovascular system, which are responsible for being a means of transport for blood with and without oxygen that reaches all tissues and returns to the heart. In very hot weather, surface thermoreceptors signal the brain that something needs to be done to dissipate heat. For this reason, a vasodilation process is activated, which allows blood to flow to the outermost layers of the skin. This promotes a heat exchange with the environment, which helps the individual to lower their body temperature. Cold causes a decrease in blood flow by reducing the size of the vessel (arteries or veins) through which blood and other substances circulate. By reducing the size of the vessel, the substances that circulate in the blood are also reduced. The heat causes an increase in the size of the blood vessels, which generates greater transport of nutrients through the blood.

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.

estuaries are the partially enclosed coastal bodies of brackish water formed at the mouth of sea where river meets an ocean. it is a transition zone between river and sea water so estuaries are influenced to both marine environment such as tides, waves and to riverine such as flow of fresh water and sediments. the mixing of sea and fresh water provide high level of nutrients, making estuaries a high product habitats.

many estuaries suffers degradation from a variety of human activities like erosion from deforestation, overgrazing, overfishing, drainage and eutrophication.

so from the above statement answers will be

1. false as estuaries are formed due to both brackish and freshwater.

2.true, due to high productivity estuaries are breeding ground for many marine species.

3. direct and indirect activities of man that contribute to pollution and deposition of sediments.