a. Processes: - Is a series of steps that manipulate data b. Data flows: - Describes the data and the information elements passing between external entities, processes and data stores c. Data stores: - A place to keep data for later use d. External entities:- The original source of data or the receiver of information
Nitrogen=2, Hydrogen=8, Carbon=1, Oxygen=3
Hydrogen=4, Carbon=2, Oxygen=2
Iron=1, Nitrogen=2, Oxygen=6
Explanation:
Steps followed to practice laboratory safety during the experiment are as follows.
- Used tongs or a test tube holder to hold materials over the Bunsen burner flame.
- Wore gloves and goggles.
- Made careful observations of the products and reactants.
- Did not smell the gases produced.
When we heat a test tube over bunsen flame then the tube gets hot and when we hold it with bare hands then out hands will burn. Therefore, it is advised to hold test tube with the help of tongs or a holder so that our hands did not burn.
We should also wear gloves and goggles so that any acid would not spill directly on our hands, skin and eyes as it can affect or damage the skin severely.
Careful observations were made so that correct calculations about the experiment can be carried out.
It is also advised that we should not smell the gases produced but gases move freely from one place to another in a laboratory or any where else.
So, we can try to avoid it by covering our mouth with a cloth but we cannot stop it. If we keep on inhaling the gases produced in a laboratory then it can also lead to severe disease or defect in the human body.
Answer: The stage of metamorphosis this occurs is called the PUPA stage. The correct option is D.
Explanation:
Metamorphosis can be defined as the change in form, mode of life and behaviour that occurs during embryonic development of an organism. In the metamorphosis of insects, which mostly reproduce sexually, insects can be grouped according to the way the eggs develop into adults. Some show:
--> Complete metamorphosis or
--> Incomplete metamorphosis.
In the life cycle of a butterfly, a COMPLETE metamorphosis occurs. This is because after fertilization, the EGG hatches into LARVA which passes through a PUPAL stage before becoming transformed into an ADULT insect. That is:
Egg --> Larva --> Pupa --> Imago.
When the caterpillar, which is the Larva stage, has reached its full size, it spins a pad of silk on a twig. It moves upward and attached it's clasper to this pad. It spin another silk thread at the thorax. These aids it to assume a slanting position with the head end pointing upwards. The pupa stage called the CHRYSALIS is reached when it tucks it's head under its thorax, arches it's body, shortens and broadens, and moults for the last time. Therefore the correct option is D (pupa).
