Answer:
The correct answer is A. 3O₂ + 2Al → 2AlO₃
Law of conservation of mass states that mass can nether be created nor destroyed in a closed system or chemical reaction i.e. the total mass of the matter always remains the same throughout the chemical or physical change.
For example, in the given reaction 3O₂ + 2Al → 2AlO₃ the total mass of the reactants is equal to the total mass of the product.
Mass of oxygen = 16 x 3 = 48 AMU
Mass of aluminium = 2 x 27 = 54 AMU
Total molecular mass of the reactants = 102 AMU
Total molecular mass of the product = 2 x 27 + 6 x 8 = 102 AMU.
Hence, the total mass of the matter remains the same.
Answer:
Prophase 1
Explanation:
Prophase I :It can be divided into five stages:
1)Leplotene: In this stage, chromosome becomes visible and shorten as a single structure.
2)Zygotene: Homologous / sister chromosome pair up. This process is known as synapse. Synapse is the process of attachment of homologous /sister chromosome. One pair comes from the male parent while the other comes from the female parent.
3)Pachytene: Bivalents shorten.
4)Diplotene:Point of attachment of non-sister chromatids. The two chromosomes are seen to be joined at several points along their length. These points are known as Chiasmata.(Chiasmata, a cross). The paternal gene A, B, C may swap for the maternal gene a, b, c for instance, leading to a new gene combination in the resulting chromatids. This is referred to as *CROSSING OVER*.
5)Diakenesis: Homologous centromere move apart.
So, crossing over occurs in *Prophase 1.
Answer:
The time between the end of ventricular systole to the beginning of atrial systole is 100 ms or 0.1 seconds.
Explanation:
Ventricular systole is the removal of blood from the heart by pumping through aorta and pulmonary vein. Both aorta and pulmonary vein receive the blood from the heart. Aorta receives oxygenated blood and pulmonary vein receive deoxygenated blood, while atrial systole is the addition of blood into the ventricular from vena cava and pulmonary artery due to contraction of heart. This process occurs in 100 ms.
Answer: hydrosphere, cryosphere, geosphere
Explanation:
Answer:
500-million-year-old fossil found in BC is ancient ancestor of spiders and scorpions. Palaeontologists in British Columbia have found a fossil of the oldest known ancestor of scorpions and spiders.
