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.
Since Tameeka is experiencing contractions, this means that she must already be in her third trimester. Contractions usually happen around 38 weeks into the pregnancy. In week 38, the baby is already at the fetal stage which is the third stage of prenatal development.
Answer: Option A.
The hypothalamus is the brain structure responsiblre for regulating thirst, hunger, temperature and sexual behaviour.
Explanation:
Hypothalamus is a part of brain structures located at the floor of the third ventricle below the thalamus and its control the autonomic system.
It controls hunger, thirst, temperature, fatigue, sleep and sexual behaviour . Hypothalamus secretes the anti diuretic hormones which increases the level of water absorbed into the blood by the kidneys and corticotropin releasing hormone which regulate immune system.
