Question

Explain billing system in brief for class 7th student

Answer 1

Answer:A billing system is a combination of software and hardware that receives call detail and service usage information, groups this information for specific accounts or customers, produces invoices, creates reports for management, and records (posts) payments made to customer accounts.

Explanation:

Answer 2

Guard cells are located in the leaf epidermis and pairs of guard cells surround and form stomatal pores, which regulate CO2 influx from the atmosphere into the leaves for photosynthetic carbon fixation. Stomatal guard cells also regulate water loss of plants via transpiration to the atmosphere.