Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): A typical unfertilized, angiosperm embryo sac at maturity is 8-nucleate and 7-celled.
Reason (R): The egg apparatus has 2 polar nuclei.
In the light of the above statements, choose the correct answer from the options given below:
A sphere of radius R is cut from a larger solid sphere of radius 2R as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the Y-axis is :
Active transport is a type of cellular transport in which molecules (such as glucose, ions, and amino acids) are transferred across a biological membrane to a place where there are already enough of them. As a result, molecules are moved across concentration gradients using chemical energy (for instance, ATP). Root hair cells and the small intestine wall are persistent active transport sites (villi).
There are two types of active transportation mechanisms such as;