In the light of the carrier concept,the transport of ions across the membrane is:

Active transport differs from passive transport in that active transport

Provide definitions/explanations for the following terms:
$(1)$ Uniport
$(2)$ Symport

Read carefully the given table and choose the option that correctly fills the blanks in it.

Property	Simple Diffusion	Facilitated Transport	Active Transport
Requires special membrane proteins	No	$a$	Yes
Transport saturates	No	Yes	$b$
Uphill transport	$c$	No	Yes
Requires $ATP$ energy	No	No	$d$

Identify the values for $a, b, c, d$.

Which of the following statements is correct?
$(I)$ Rapid uptake of ions into the free space is a passive process.
$(II)$ Apoplast is important for passive processes.
$(III)$ Metabolic energy is required in passive processes.
$(IV)$ In the apoplast,passive processes occur through ion channels.

Active transport