Genetic variation is essential for natural selection because natural selection can only increase or decrease frequency of alleles that already exist in the population. Genetic variation is caused by: mutation. random mating between organisms
Answer:
The correct answer would be B. Lungs, left ventricle, capillaries, veins, right ventricle.
It can be explained with the help of double circulation.
The oxygenated blood from the lungs is transported to the left atrium with the help of pulmonary veins.
The left atrium then passes the oxygenated blood to the left ventricle which passes the blood to all parts of the body via aorta.
The artery then divides into fine capillaries which supply cells and tissues of the body.
The cells use the oxygen and produce carbon dioxide as the byproduct of cellular respiration.
The blood is now termed as deoxygenated blood which is carried out by veins.
Vein transport this blood to the right atrium of the heart which passes the same to the right ventricle.
Left ventricle then pumps the blood towards lungs for oxygenation.
Answer:
The correct answer will be- anterior horn cells
Explanation:
The upper motor neurons in the system of motor neurons of the central nervous system.
The motor neurons transmit the signals from the CNS to the skeletal muscles and thus controls the voluntary movement and maintain the posture of the body.
The motor neurons of the upper system synapse with the lower motor neurons in the cell bodies of the lower motor neurons located in the grey matter of the spinal cord.
The cell bodies where upper neurons synapse with lower neurons are known as anterior horn cells in which the interneurons connect these neurons.
Thus, anterior horn cells are the correct answer.
Plants and animals need nitrogen to make amino acids, proteins and DNA, but the nitrogen in the atmosphere is not in a form that they can use.
Answer: ultrasound
Explanation:
reflection of sound method