Answer:
<u>A common element among all the river valley civilizations was irrigation systems that moved water to crops and settlements</u>
Explanation:
- <u>River Valley civilizations where the civilizations that were found on the banks of the river like the Mesopotamia ,Indus valley civilization.</u>
- <u>These civilization where agriculture based civilization as they depended on river for drinking water and irrigational activities</u>
Answer:
the 4th one The lumen, is my guess
Answer:
Three different kinds of muscles are -:
- <u>SKELETAL MUSCELES </u>
- <u>CARDIAC MUSCLES </u>
- <u>SMOOTH MUSCLES</u>
Explanation:
- <u>SKELETAL MUSCLES -: </u>There are long, cylindrical, and striated skeletal muscle cells. They are multi-nucleated, which means they have more than one nucleus. This is because from the fusion of embryonic myoblasts, they are created. Each nucleus controls the sarcoplasm's metabolic demands around it. There are high energy requirements for skeletal muscle cells, because they contain several mitochondria in order to generate adequate ATP. <u>Examples of skeletal muscles: arms and legs- </u>T<u>he muscles that belong to the arms and legs feature in pairs. Abdomen and Back- These muscles are connected to the various sets of skeletal muscles that run across the torso.</u>
- <u>CARDIAC MUSCLES -</u>: Cardiomyocytes have a short and narrow outline and are fairly rectangular. They are about 0.02 mm wide and 0.1 mm (millimetres) long, respectively. There are many sarcosomes in cardiomyocytes, which provide the required energy for contraction. Cardiomyocytes usually contain a single nucleus, unlike skeletal muscle cells. Cardiomyocytes, although they contain more sarcosomes, normally contain the same cell organelles as skeletal muscle cells.<u> example - cardiac muscle is present in heart. </u>
- <u>SMOOTH MUSCLES -:</u> Smooth muscle cells have a single central nucleus and are spindle-shaped. They range in length from 10 to 600 μm (micrometers), and are the tiniest type of muscle cell. In the expansion of organs like the kidneys , lungs, and vagina, they are elastic and therefore essential. As in cardiac and skeletal muscle, the myofibrils of smooth muscle cells are not aligned, meaning they are not striated, hence the term smooth. <u>example of smooth muscles -: Walls of blood vessels , Walls of stomach ,
Ureters , Intestines , In the aorta (tunica media layer), Iris of the eye. ,Prostate and Gastrointestinal Tract.</u>
Answer:
true
Explanation:
Cerebrospinal fluids is a colorless fluid that is secreted in the choroid plexus,and circulates in the ventricles system and sub -aranchinoid space of the brain and spinal cord. its provides nutrients to the surrounding neurons, cushions the effects of trauma, pressure, acts as buffer and provides protection through immune system .
it plays a vital role in regulating blood flow, through a process called cerebral auto regulation,This is needed to maintain efficient cerebral blood flow of oxygen and other metabolites, and withdraw of metabolic wastes from the brain.
in order to analyze it to diagnose some neurological diseases its sample is usually taken out in a process called lumbar puncture.
