Answer:
Education is an important topic in Mark Mathabane’s autobiography because when he was growing up in South Africa, the apartheid system made it very difficult for a black child to get anything close to an adequate education. The experiences Mathabane relates, however, extend far beyond attending school.
The role of African traditional culture, which Mark (previously Johannes) learned from his mother, also played a significant role. His mother could not read but had learned and transmitted the cultural information orally. From his mother, he also learned optimism about his own place in the world and the possibilities for black Africans in their country, which helped counter the negativity his father held and expressed.
Answer: from the mouth to stomach
Explanation: mechanical digestion takes place when the food travels down from the mouth to stomach. Chemical digestion occurs from the mouth to intestine.
Answer: A.
The US will import more from Japan.
Explanation: I did this on Edge
Answer:
The age of the rock = 2800.6 million years = 2.8 billion years.
A simple method of analysis similar to Carbon dating is used to obtain the required age of the rock. Radioactive substances decay according to first order reaction kinetics. So, plugging all the required parameters into the general equation for amount of substance left in a first order decay gives us the age of the rock.
Explanation:
Half life of Uranium-235 = 700 million years (from literature)
The decay of radioactive substances follow first order reaction kinetics.
The general equation is given as
A(t) = A₀ e⁻ᵏᵗ
A(t) = Amount of radioactive substance left after a particular time = 6.25%
A₀ = initial amount of radioactive substance = 100%
t = time that has passed since the beginning = age of the rock = ?
k = decay constant
The decay constant is related to the half life (T) through the relation,
k = (In 2)/T
k = (0.693/700) = 0.00099 /million years
A(t) = A₀ e⁻ᵏᵗ
6.25 = 100 e⁻ᵏᵗ
0.0625 = e⁻ᵏᵗ
In e⁻ᵏᵗ = In 0.0625 = -2.7726
-kt = - 2.7726
t = (2.7726/0.00099) = 2800.6 million years
t = 2.8 billion years.
Hope this Helps!!!
