Answer:
Gastrulation.
Explanation:
Zygote is formed by the fusion of the male and female gamete. The zygote undergoes the process of cleavage to form the different embryonic stages of the offspring.
Gastrulation is the important process of the pre embryonic development. The blastula get multiply and rearranged to form the gastrula. The gsatrulation process includes the formation of three germ layers also known as triploblastic embryo. The three germ layers are ectoderm, endoderm and mesoderm.
Thus, the correct answer is option (C).
Answer: B. pressure changes in the thorax
Explanation:
The veins are the blood vessels which returns the deoxygenated blood from all the tissues and cells of the body back to the heart. The ventricular systole, venous valves, activity of the skeletal muscles and neural control over venoconstriction all influence the movement of the blood in the venous.
The pressure changes in the thorax occurs due to inspiration and expiration. During the process of inspiration, the diaphragm below the lungs contracts and moves downward while the muscles of the ribs pulls downward. When the size of the thoracic cavity increase the air pressure inside the cavity decreases and vice-versa. The pressure inside the thoracic cavity is not related with the movement of the venous blood as it regulates the exchange of the gases not the blood.
Oxygen is the common characteristic which helps fire to burn and a flowering plant to live on earth. When oxygen combines with a suitable chemical, it releases energy in the form of heat.
Answer:
The given statement is false.
A neuron is the basic structural and functional unit of the nervous system. It helps in transmitting information from one neuron to another neuron, gland, or muscle cell.
The conduction of nerve impulse is electrochemical in nature. It transmits the impulse electrically through the axon the nerve cells and chemically through synapses (gap between two nerves cells).
The axon terminals of pre-synaptic nerve cell release chemical messengers (also called neurotransmitters) in the synaptic cleft. These messengers then bind to the receptors present on the post-synaptic nerve cell and regenerate the nerve impulse.
