A. It forms a part of the upper atmosphere known as the ozone layer.
The conduction of nerve impulses relies upon the movement of positively-charged ions across the nerve cell membrane. The entry of sodium into the cell produces a wave of positive charge that travels down the length of an axon. Then chemicals called neurotransmitters are secreted out of the end of the axon onto the next nerve in the series (the postsynpatic nerve). This narrow space in between neurons is called the synapse. These neurotransmiiters released by the presynaptic nerve bind to receptors on the postsynaptic nerve. The binding of these receptors opens up channels in this second nerve's membrane that allow sodium ions to enter the nerve cell and initiate another wave of positive charge, and so on... The nerve signal can only move as fast as these ions and neurotransmitters can diffuse to generate this process.
<span>As a professional athlete repeats a given activity many times over, the nerve cells "upregulate" their receptors, meaning that they produce additional receptors to put in the membrane. This is just a natural reaction to the nerve being repeatedly stimulated in the same way over and over. When neurotransmitter is secreted from the presynaptic neuron, there are more receptors on the postsynaptic neuron for it to bind, more channels open up, more ions enter in a shorter time and build up positive charge to create the impulse faster, and so the overall effect is faster. </span>
<span>Additionally, there are sheaths of fatty tissue (called myelin) that insulate the charge in the neuron and allow it to be conducted faster. As people age, these sheaths can start to degrade, making the nerve cell more "leaky" and causing the impulse to be conducted more slowly. </span>
Pampas and Patagonia
The Pampas are prolific South American marshes that comprise more than 750,000 km2 and combine the Argentine territories of Buenos Aires, La Pampa, Santa Fe, Entre Ríos and Cordoba. The vast fields are a common region, suspended only by the low Ventana and Tandil hills, near Bahia Blanca and Tandil Argentina, with an elevation of 1,300 m (4,265 ft) and 500 m (1,640 ft), sequentially.
Patagonia is a sparsely populated area at the southerly end of South America, administered by Argentina and Chile. The district encompasses the southerly segment of the Andes hills and the sands, pampas, and meadows to the east. Patagonia is one of the rare areas with shores on three oceans, with the Pacific Ocean to the westward, the Atlantic Ocean to the east, and the Southern Ocean to the South land.
Answer:
The correct answer will be option-D
Explanation:
The evolution of vascular tissues in plants from non-vascular plants was an adaptive feature to survive in the terrestrial environment. The group of plants in which vascular tissues evolved and developed is the Pteridophytes which contained stellar organization of the vascular bundles.
The pteridophytes exhibited xylem and phloem which allows the rapid uptake of the water and nutrients from the soil which allowed the growth of the plant and since plants got enough water and nutrients from the soil, they adapted to grow tall so that they can maximize the output of photosynthesis in bright sunshine.
Thus, option-D is the correct answer.
Chao should use a flat shallow pan filled with a thick liquid that can be heated by a hot plate with pieces of thin plastic sheets floating on top of the liquid. This part of the experiment will best depict plate tectonics because of the variables that can be seen
hope this helps
