Health and Human Body - I

A missing fingernail takes 4 to 5 months to grow back.

Lungs are the essential respiratory organ and its principal is to transport oxygen from atmosphere into the bloodstream.

Unbiblical cord is an essential organ, <span style="font-family:" arial;="" font-size:="" small;="">which passes the blood between the fetus and the placenta.

The liver is the largest gland in the human body. It is located in the right upper quadrant of the abdominal cavity.

Liver helps in fighting infections by synthesizing antibodies, regulates the blood clotting  and produces bile which helps in digestion of fats.

A humerus is a long bone in the arm or forelimb which extends from the shoulder to the elbow.

Blood group O does not have any antigen on its surface and can be donated to individual containing any blood group.

 Canines are sharp pointed teeth. These are called dog teeth as dog's dentition consist mostly of canines.

Eye pupil is the only part of human body that can increase to eight times its smallest size.

Ribosomes are cellular organelles composed of RNA and proteins that synthesize proteins. They exist in large numbers in the cytoplasm. RNA alone is just a nucleic acid, DNA carries genetic information, and cytoplasmic acid is not a standard cellular structure.

The heart (cardiac muscle) is considered the strongest because it contracts continuously without rest throughout a lifetime. While the masseter (jaw) muscle generates more force per contraction, it cannot sustain this output continuously like the heart.

There are essentially 3 types of muscles in the humans body, those are skeletal, cardiac and smooth.

The receptor is the right answer as it reserves the chemical signals externally from the calls.

Metamorphism is the process when a young organism that looks nothing like an adult, becomes an adult. It is not a necessary life process because not all species go through it.

Hair, bird feathers, and dog claws are all composed primarily of keratin - a tough, fibrous structural protein. Teeth are enamel/dentin, earlobes are connective tissue/fat, eyelashes are also hair (keratin), and eyes contain various tissues.