Answer:
Explanation:
We are asked to find how much of a 40 gram sample remains after 12 years.
Iron-55 has a half-life of 3 years. Therefore, after 12 years, 4 half-lives have been completed.
- 12 years/3 years = 4 half-lives
Every time a half-life is completed, half of the sample's mass decays. Remember we start with a 40 gram sample.
- 1 half- life: 40 g / 2 = 20 g
- 2 half-lives: 20 g / 2= 10 g
- 3 half-lives: 10 g / 2 = 5 g
- 4 half-lives: 5 g / 2 = 2.5 g
There is also a formula that can be used to solve this problem.
Where A₀ is the initial amount, t is the time, and hl is the half-life.
We know 40 grams is the inital amount, 12 years is the time, and 3 years is the halflife.
After 12 years, <u>2.5 grams </u> of Iron-55 will remain.
Answer:
The nervous system helps all the parts of the body to communicate with each other. It also reacts to changes both outside and inside the body. The nervous system uses both electrical and chemical means to send and receive messages.
Explanation:
The correct answer is option B, that is, the release of large amounts of greenhouse gases can change Earth's climate.
Fossil fuels refer to hydrocarbons, mainly fuel oil, coal, or natural gas, produced from the leftovers of dead animals and plants. The use of fossil fuels has allowed large-scale industrial development and hugely supplanted water-driven mills, as well as the combustion of peat or wood for heat.
The burning of fossil fuels by humans is the biggest source of emissions of carbon dioxide that is, one of the greenhouse gases, which permits radioactive forcing and donates to global warming. One of the dreadful effects of global warming is the change in the climatic condition of Earth.
Answer:
The correct answer will be option-B.
Explanation:
The plant tissues are composed of three types of cells: parenchyma, collenchyma and sclerenchyma.
The parenchyma and collenchyma remain alive at their maturity but sclerenchyma loses their protoplasm and become dead. These cells deposit lignin in their secondary walls and form hard tissues of the plant-like hard shell of a coconut. Sclerenchyma provides mechanical strength to the plant.
Thus, Option-B is the correct answer.
<span>The correct answer should be that the carnivore population would also increase. Since they eat the herbivores, if the amount of herbivores increased there would be more food for the carnivores so they wouldn't have to worry about anything and could thrive, feeding themselves without worrying for food.</span>
