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:
A transport protein is a type of protein that helps an organism move other materials around. Transport proteins are essential for all living organisms' development and survival. Transport proteins come in a variety of shapes and sizes.
<u>OAmalOHopeO</u>
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Its C. ATCGGAT And then C is missing GG
Answer:
where are the answer choices?
Explanation:
..................
The symptoms given may be a manifestation of Polycystic
Ovary Syndrome (PCOS), which is a common endocrine system disease among
females.
Symptoms are the following:
<span>1. </span>Menstrual disorders: oligomenorrhea (irregular
period) or amenorrhea (cessation of period), which start around the time of the
first period (menarche)
<span>2. </span>Infertility: which results from anovulation
(ovaries are unable to release an egg cell during ovulation)
<span>3. </span>Obesity: at least 40% of females with PCOS are
obese
<span>4. </span>Hirsutism (excessive body hair where hair is usually
minimal or absent): big amount of
masculinizing hormones in women with PCOS may cause hirsutism