Question

Why is this wrong: all autotrophs perform photosynthesis

why do guard cells close during hot, dry conditions

Answer 1

Autotrophs are organisms that can produce their own food from inorganic materials.They include green plants,phytoplankton,algae,cynobacteria.Most of the autotrophs use photosynthesis to make their own food but some can get their food by chemosynthesis.Chemosynthesis is the process of producing food without the use of sunlight,they get the energy from chemical reactions.

Guard cells are the cells which are found in the epidermis of the leaves and surrounds the stomata.Its main function is to control the exchange of gases by closing and opening the stomata.When there is a need for opening the stomata during the photosynthesis to take in the carbondioxide the water flows into the guard cells which opens the stomata.But during hot conditions the stomata must be closed to prevent the evaporation of water,in that case the water from the guard cell moves to the surrounding cells where there is more solute potential.