Q1. The answer is 1.
It can be calculated using the equation:
(1/2)ⁿ = x
x - decimal amount remaining,
n - a number of half-lives.
x = 50% = 50/100 = 0.5
n = ?
(1/2)ⁿ = 0.5
log((1/2)ⁿ) = log(0.5)
n * log(1/2) = log(0.5)
n * log(0.5) = log(0.5)
n = log(0.5)/log(0.5)
n = 1
Q10. The answer is 2.
It can be calculated using the equation:
(1/2)ⁿ = x
x - decimal amount remaining,
n - a number of half-lives.
Rhyolite #2 has 25% of the parent H remaining:
x = 25% = 25/100 = 0.25
n = ?
(1/2)ⁿ = 0.25
log((1/2)ⁿ) = log(0.25)
n * log(1/2) = log(0.25)
n * log(0.5) = log(0.25)
n = log(0.25)/log(0.5)
n = -0.602 / - 0.301
n = 2
Q3. The answer is 100 million years.
A number of half-lives (n) is a quotient of total time elapsed (t) and length of half-life (H):
n = t/H
n = 1
t = ?
H = 100 000 000 years
n = t/H
t = n * H
t = 1 * 100 000 000 years
t = 100 000 000 years<span>
</span>
The walls of xylem cells are lignified (strengthened with a substance called lignin ). This allows the xylem to withstand pressure changes as water moves through the plant.
The cell membrane is flexible because of the presence of oil like substances called phospholipids, which gives it a fluid nature. While as the cell walls are rigid because of the presence of the thick layers of the substances like cellulose in plants, chitin in fungi and peptidoglycon in bacteria.
Answer:
B (active transport using ATP)
Explanation:
Movement of substances normally occur in the direction of concentration gradient/difference i.e. the difference in concentration of a substance across a membrane. Letting molecules diffuse or pass down their concentration gradient does not require energy but pumping those molecules against gradient requires energy in form of Adenosine triphosphate (ATP). This process is called Active transport.
In order to perform certain cellular processes, cells need to move substances from their surroundings into the cell across their cell membrane. Moving this substances against the concentration gradient between the cell membrane and its extracellular fluid requires energy (ATP).
An example is the sodium-pottasium pump employed by animal cells in which they expend energy to move K+ molecules into the cell and Na+ molecules outside the cell against the concentration gradient of their cell membrane and extracellular solution.
Answer:
The microorganism creates its own energy.
Explanation:
Based on the pattern of nutrition, a living organism can either be autotrophic or heterotrophic. Autotrophic organisms are those organisms capable of synthesizing its own food or energy source using light (photosynthesis) or chemicals (chemosynthesis). Heterotrophs, on the other hand, cannot synthesize their own food, hence, they depend on other organisms for energy.
According to this question, a researcher claims that a newly discovered microorganism is an autotroph. For this claim to be true, this means that the microorganism must be capable of CREATING ITS OWN FOOD/ENERGY either by photosynthesis (light) or chemosynthesis (inorganic chemicals).
