Biology Questions

The lymphatic system is a complex system of fluid drainage and transport, and immune response and disease resistance. Fluid that is forced out of the bloodstream during normal circulation is filtered through lymph nodes to remove bacteria, abnormal cells and other matter. This fluid is then transported back into the bloodstream via the lymph vessels. Lymph only moves in one direction, toward the heart.

The basic unit of the nervous system is the Neurons.

The neuron is a single nerve cell, and you have billions of them.

There are three basic types of neurons::

1. Association,

2. Afferent  and

3. Efferent.

The association neurons comprise the central nervous system (CNS) that is the brain and spinal cord.

The afferent neurons are also known as the sensory neurons, they bring the stimuli from the sensors (e.g., skin, eyes, ears) to the CNS.

The efferent neurons are also known as motor neurons, they bring the responses from the brain to the muscles and the glands.

In cancer cells, there is breakdown of these regulatory mechanisms. Normal cells show a property called contact inhibition by virtue of which contact with other cells inhibits their uncontrolled growth. Cancer cells appears to have lost this property. As a result of this, cancerous cells just continue to divide giving rise to masses of cells called tumors. Tumors are of two types: benign and malignant.

The correct order of evolutionary history from the above given options is jellyfish, reptiles, mammals.

Tuber is considered as a modified stem. These type of stems carry out special functions that are important for the plant to survive. Tubers serves as a food reserve and bearing buds wherein new plants can grow.