Answer:
B. all organisms are made of at least one cell.
C.cells are the building blocks of life.
D.all cells come from preexisting cells
Explanation:
According to the cell theory that was proposed via the contribution of three scientists in 1830's namely: Matthias Schleiden, Theodor Schwann, and Rudolf Virchow, the following was stated:
- Cells are the basic and fundamental unit of life
- Living organisms are made up of one or more cells
- All cells arise from pre-existing cells.
From the above components, the following are said to be true and correlate with the universal cell theory:
B. all organisms are made of at least one cell.
C.cells are the building blocks of life.
D.all cells come from preexisting cells
Answer : The age of the rock is, 2.60 billion years
Explanation :
Half-life = 1.3 billion years
First we have to calculate the rate constant, we use the formula :
Now we have to calculate the time passed.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant =
t = time passed by the sample = ?
a = initial amount of the reactant = 12 mg
a - x = amount left after decay process = 3 mg
Now put all the given values in above equation, we get
Therefore, the age of the rock is, 2.60 billion years
Answer:
Option D. 230 J
Explanation:
We'll begin by calculating the temperature change of the iron. This can be obtained as follow:
Initial temperature (T₁) = 50 °C
Final temperature (T₂) = 75 °C
Change in temperature (ΔT) =?
ΔT = T₂ – T₁
ΔT = 75 – 50
ΔT = 25 °C
Thus, the temperature change of the iron is 25 °C.
Finally, we shall determine the amount of heat energy used. This can be obtained as follow:
Mass (M) = 20 g
Change in temperature (ΔT) = 25 °C
Specific heat capacity (C) = 0.46 J/gºC
Heat (Q) =?
Q = MCΔT
Q = 20 × 0.46 × 25
Q = 230 J
Thus, the amount of heat used was 230 J