The double layered sac surrounding the heart is the pericardium
The defense system of the human body is made up of entire organs and vessel systems like the lymph vessels, but also of individual cells and proteins. The inner and outer surfaces of the body are the first barriers against pathogens (germs). These surfaces include the skin and all mucous membranes, which form a kind of mechanical protective wall.
Several things support this protective wall:
<span><span>- The body’s own antibacterial substances can disable different pathogens from the environment at an early stage. A certain enzyme found in saliva, the airways and tear fluid destroys the cell walls of bacteria.
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- Many pathogens that are breathed in get stuck to mucus in the bronchi and are then moved out of the airways by hair-like structures called cilia.
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- Most pathogens that enter the body together with food are usually stopped by stomach acid.
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- Normal flora, harmless bacteria that reside on the skin and many mucous membranes in the body, also help to protect the body.</span></span>
The cough and sneeze reflex can also help to remove pathogens.
Hope this helps (:
Answer:
ladybugs have spots because they are part of a ladybugs clever color scheme ladybugs produce alkaloids, toxic chemicals that make them unparable to hungry spiders, ants, or other predator's
Plant the seeds after they cut them my dood. thanks for the points.
Answer:
Firstly, they are all biogeochemical cycles. They cycle substances through the different systems. So this means that these substances like elements, compounds, and the like go through the hydrosphere, atmosphere, geosphere, and biosphere. It involves both the living and non-living things on Earth, all playing a role in transforming substances into something that can be used, only to be recycled again to provide for the other in a cyclic manner.
For example the oxygen cycle involves how oxygen is produced and used over and over. As we exhale Carbon Dioxide, it gets absorbed by plants which use it, along with water and light, to produce their own food in a process called photosynthesis. A by-product of this process is oxygen which we take in and use and we exhale Carbon dioxide again.
