What is the membrane surrounding the heart called?

The coefficient of apparent expansion of a liquid when determined using two different vessels $A$ and $B$ are $\gamma_1$ and $\gamma_2$ respectively. If the coefficient of linear expansion of the vessel $A$ is $\alpha$,then find the coefficient of linear expansion of vessel $B$.

The function $f(x) = |x| + \frac{|x|}{x}$ is

The coordination number of a metal crystallizing in a hexagonal close-packed structure is

Identify the plant and structure marked $A$ and $B:-$

What is the primary purpose of data entry in the context of mathematical research?