Answer:
double helix
Explanation:
Together, a base, sugar, and phosphate are called a nucleotide. Nucleotides are arranged in two long strands that form a spiral called a double helix
The right answer is vein (it contains blood and has valves).
The infra-cardiac veins of small and medium caliber possess this system of fight against gravity. The valves consist of a dense connective tissue, surmounted by endothelial cells, corresponding to a fold of the intima. They allow blood circulation in the sense organ / heart but prevent venous reflux.
Answer:
1.abiotic- air and biotic-birds
2.producing delicious and good fruits for animals protect and help them to spread. delicious food attract animals like birds and other animals who are feed on them. when they eat the fruits and the seeds pass by unharmed. these way the seed dispersal occur of a plants.
During acclimatization over a few days to weeks, the body produces more red blood cells to counteract the lower oxygen saturation in blood in high altitudes. Full adaptation to high altitude is achieved when the increase of red blood cells reaches a plateau and stops.Heart rate is controlled by the two branches of the autonomic (involuntary) nervous system. The sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). ... At the beginning of exercise, your body removes the parasympathetic stimulation, which enables the heart rate to gradually increase.
D)all of them
Nutrients enter a cell up the concentration gradient by the process of active transport.
