Answer:
oxygen
Explanation:
Everything needs oxygen, even your cells because oxygen is crucial in process of ATP production which basically powers all of our actions. Hence, when you cells have low O2 your muscles will tire out quickly due to lack of energy thus you need to replenish them with Oxygen so that you can put an end to fatigue.
Answer:
D. By blocking fish migration.
Explanation:
The pictured waterfalls are artificial.
The construction of the wall to raise water level for the falls to be created cuts the contact between marine organisms.
The fish on the other end of the fall cannot freely migrate to the other side.
This is because the falls are too dangerous for them and can lead to their death.
This means that the pictured method of power generation is not environmental friendly.
The brain, heart and the skeleton are the integral parts of the nervous system, circulatory system and the skeletal system respectively. The nervous system is made of the brain and the spinal cord with neurons as the structural and functional units of it. The circulatory system is made up of the heart and its blood vessels. The skeletal system is made up of the bones and cartilages making the skeleton of the body.
The brain regulates the heart beat and the blood pressure. The heart nourishes the brain with oxygen and nutrients by pumping blood. The bone cells are nourished by the blood pumped by the heart. The bone marrow of the skeleton produces the new red blood cells which enter the blood circulatory system. Also the the ribs and the breast bone of the skeleton protects the heart, the cranium of the skeleton prtects the brain. The bones also provide calcium which is necessory for the functioning of the nervous system. The brain controls the skeletal movements of the body. The cerebellum of the brain controls the voluntary skeletal movements and the medulla controls the involuntary skeletal movements of the body. The blood brain barrier formed by the endothelial cells of the capillary walls located in the brain seperates the circulating blood from the brain and the extraclellular fluid in the central nervous system and acts as a selective semipermeable border.
They overgrazed on the parks vegetation and grasses.
Answer:
Before answer this question, you need to know what is the half-life of a compound, the term half-life is defined as the time it takes for one-half of the atoms of a radioactive material to disintegrate. Knowing this you know that has passed half of the half-time, so you should probably have 25% of the original amount of 235U. This problem may be tricky because it says half of the time to reach the half-time, but 50% of the compound will be present in 750 million years after the death of the specimen.
