Answer: James Watson and Francis Crick
Explanation:
In 1953 James Watson and Francis Crick are responsible for determining the structure of DNA. James and Watson proposed that the DNA is made up of a double polynucleotide chains that are twisted around each other to forming a helical structure. The two DNA chains runs anti-parallel in opposite direction to each other. Like the structure of the ladder.
The answer is James Watson and Francis Crick
The major evolutionary episode corresponding most closely in time with the formation of Pangaea was the Permian Extinctions.
The Permian Extinctions happened around 300 million years ago and lasted for around 15 million years. It eliminated over 95 percent of water life and 70 percent of species on land. It was one of the largest extinctions in the history of Earth.
Answer: net primary productivity is the amount of energy lost through respiration by producers SUBTRACTED From the gross primary productivity of an ecosystem
The nervous system and the muscle system respond to stimuli to produce motion. The skeletal movements of muscles are mostly voluntary.
Involuntary movements occur in these muscles when the nerve impulse passes from a sensory neuron to a motor neuron via an interneuron in the spinal cord.
<h3>What are Skeletal muscles?</h3>
Skeletal muscles may be defined as the muscles that fasten to your bones and authorize you to achieve a broad range of activities and operations.
Skeletal muscles control the direct movement of a person's will and are hence referred to as voluntary movement.
While the spinal cord is associated with both movements directly or indirectly. It is a prolonged, delicate tubelike network liable for holding incoming and outgoing messages through the brain to the rest body.
Therefore, it is well described above.
To learn more about Skeletal muscles, refer to the link:
brainly.com/question/1283837
#SPJ1
Answer:
d. xylem and phloem
Explanation: plants possess vascular bundles.these are bundles which includes xylem and phloem tissues and transport useful substances to various plant cells.
New Xylem and phloem are formed from the vascular cambium which divides into new cells .
Xylem and phloem are thin and slender with pipe-like structure.
The xylem transports water and dissolved nutrients to the cells where they are needed.
The phloem transports the product of photosynthesis (sugar) to parts what they are used up or stored .
Xylem cells are dead and consists in vessels,trachieds and xylem parenchyma.
Phloem cells are dead and consists in sieves cell, companion cells, phloem parenchyma and phloem fibres.
