Answer:
A shark's skeleton is made of cartilage , a type of strong but flexible tissue .Most other fish are covered in smooth , flat scales . A shark is covered in sharp , toothlike scales called denticles . Most other fish have flaps over their gills.
Explanation:
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Answer:
A. is palisade mesophyll
B. is spongy mesophyll
EXPLANATION OF PALISADE MESOPHYLL
- Palisade cells are found in the mesophyll of a leaf and their main function is the absorption of light so that photosynthesis can take place.
- The palisade mesophyll consists of chloroplasts with chlorophyll that absorb the light energy
- The mesophyll layer is made up of the palisade cell and spongy parts. #answerwithquality #BAL
They could improve the experiment that they made by adding another variable such as: watering the plants with fresh water. This way they could have a better comparison how plants grow based on the type of water they are exposed with.
A Nerve electrical impulse only travels in one direction. There are several reasons nerve impulses only travel in one direction. The most important is synaptic transport.
In order for a "nerve impulse" to pass from cell to cell, it must cross synaptic junctions. The nerve cells are lined up head to tail all the way down a nerve track, and are not connected, but have tiny gaps between them and the next cell. These tiny gaps are called synapses.
When you get a nerve firing, you have probably heard that it is an electrical impulse that carries the signal. This is true, but it is not electrical in the same way your wall outlet works. This is electrochemical energy. Neurotransmitters are molecules that fit like a lock and key into a specific receptor. The receptor is located on the next cell in the line. When the neurotransmitter hits the receptor on the next cell in line, it signals that cell to begin a firing as well.
This will continue all the way down the length of the nerve track. In a nutshell, a nerve firing results in a chain reaction down the nerve cell's axon, or stemlike section. Sodium (Na+) ions flow in, potassium (K+) ions flow out, and we get an electrochemical gradient flowing down the length of the cell. You can think of it as a line of gunpowder that someone lit, with the flame traveling down the length of it. Common electrical power is more like a hose full of water, and when you put pressure on one end, the water shoots out the other.
Therefore, nerve impulses cannot travel in the opposite direction, because nerve cells only have neurotransmitter storage vesicles going one way, and receptors in one place.
Cells are organized into tissues, which are then organized into organs, and are finally organized into organ systems.
Systems are composed of different organs working together to carry out a common function or purpose. For example, the stomach, pancreas, intestines, are organs that are part of the digestive system, which breaks down the food we eat to give nourishment to our body.
Similarly, organs are made up of similar tissues carrying out a common function, and tissues are made up of cells of the same kind or type, also carrying out a common function or purpose.
