The predominant hypothesis for why the animals needed some 3 billion years to evolve after the life first appeared on the planet is that the conditions were not right for them to appear.
The life on Earth has appeared much earlier that what we normally assume, and also it has not been evolving very quickly, but instead it has been a very slow and gradual process. The reason for that is that the living conditions on the Earth were much different than what are they now, or anytime from the Cambrian period until the present.
The surface was still pretty hot, and there was intense volcanic activity. The composition of the atmosphere was not suitable for animals to appear at all, and in fact it would have been toxic for them. The water too had chemicals in it that were not providing the right conditions for animals to evolve. It was only after the plants started to appear and managed to make lot of changes in the water, atmosphere, and land, than the animals were able to evolve and develop.
I believe the answer you're looking for is Evolution.
Answer:
The main properties of water are its polarity, cohesion, adhesion, surface tension, high specific heat, and evaporative cooling. A water molecule is slightly charged on both ends. This is because oxygen is more electronegative than hydrogen.
Explanation:
Answer:
A, C, F
Explanation:
I honestly am not comepletely sure about thsi one, but consider this.
1. a.) The cookie is first ingested through the mouth, where salivary glands help moisten the food, making it easier to swallow.
b.) The bolus moves down a muscular passageway called the esophagus. Two special types of muscles help push the food down into the stomach.
c.) The stomach receives the food and releases stomach acid to help digest the food. Other specialized muscles called involuntary muscles (muscles that move without conscious control of your brain) shift the food around to cover it in stomach acid. When it is liquefied, it is called chyme. The chyme is passed on to the...
d.) Small intestine. This is another passageway that measures at least 30 feet long when stretched out. The chyme moves through all 30 feet and is digested even further by special enzymes fro the liver and pancreas. Small comb-like structures called villi absorb the nutrients from the chyme as it passes. Cells living inside the villi absorb the nutrients into the bloodstream.
e.) Final stop, the large intestine. Any remaining undigested material ends up here. Water is absorbed, and whatever is left exits the body as solid waste.
2. a.) Scotty is first absorbed through the nasal cavity during the process of inhalation. The lungs inflate due to the flexing of the diaphragm.
b.) He then passes through the pharynx, another cavity that connects the nasal cavity with the...
c.) Trachea. Also referred to as a windpipe, this is a tube that runs down your neck and into your chest. The trachea also holds the larynx, or voice box. Just below your collarbone, the trachea splits in half, dividing into the left and right lungs (the right lung is larger due to the placement of the heart.). These divisions are called bronchi. These divide into even smaller branches called bronchioles. These form an entore network within the lungs called the bronchial tree.
d.) Oxygen molecules absorbed from food (Scotty's siblings) are carried into the lungs by the pulmonary artery. They move across the alveolar membrane into the alveoli network. This network contains thousands of tiny sacs in which the molecules are exchanged. Carbon dioxide is also absorbed during the process, but is later expelled through exhalation or expiration. the diaphragm and lungs all return to their original shape and placement.
3. a.) The right atrium is located in the upper left hand corner of your heart. Deoxygenated blood is released into the right ventricle. It is first absorbed into the superior vena cava, a chamber slightly above the right atrium, and then released from the inferior vena cava.
b.) The deoxygenated blood is moved into the pulmonary valve, which closes right after, and into the pulmonary artery. The deoxygenated red blood cell is taken down to the lungs to be oxygenated. This cycles throughout the veins in your body and returns to the heart via the left atrium.
c.) The newly oxygenated blood is forced into the main artery of your body (aorta). The red blood cell is carried throughout the entire network of veins. It is transported to the smallest arteries, called capillaries. A process called diffusion occurs, and the oxygen and carbon dioxide is removed from the red blood cells to be redistributed to other parts of the body. Our red blood cell is now deoxygenated, and then is transported into the small veins called venules. The blood is carried into the main vein (vena cava). The blood cell is pumped back into the right atrium, where the whole process begins again.
4. Urine is first formed in the renal artery. These are part of a structure called the renal pyramid, located in your kidney. There are about a dozen renal pyramids in your body. The renal arteries collect urea. This waste is combined with water and stored in the urinary bladder until it is ready to leave the bladder through the urethra.
