2. Given $n(n \geqslant 8)$ positive real numbers $a_{1}, a_{2}, \cdots, a_{n}$ satisfying $a_{n}=a_{1} q^{n-1}$, where $q$ is a positive number not equal to 1. Then the relationship between $a_{1}+a_{8}$ and $a_{4}+a_{5}$ is ( ).
(A) greater than
(B) equal to
(C) less than
(D) cannot be determined
2. A.
$$
\begin{array}{l}
\left(a_{1}+a_{8}\right)-\left(a_{4}+a_{5}\right) \\
=\left(a_{1}+a_{1} q^{7}\right)-\left(a_{1} q^{3}+a_{1} q^{4}\right) \\
=a_{1}\left(1+q^{7}-q^{3}-q^{4}\right) \\
=a_{1}\left(1-q^{3}\right)\left(1-q^{4}\right) \\
=a_{1}(1-q)^{2}(1+q)\left(1+q^{2}\right)\left(1+q+q^{2}\right) .
\end{array}
$$

Given \( a_{1}>0 \) and \( q \) is a positive number not equal to 1, then
$$
\left(a_{1}+a_{8}\right)-\left(a_{4}+a_{5}\right)>0 .
$$