Answer:
The correct option is: a. Tardigrades can survive both extreme heat and extreme cold.
Step-by-step explanation:
Tardigrade, also called the moss piglet or water bear, is a phylum of the most resilient micro-animals that can survive in extreme environmental conditions like dehydration, extreme pressure and temperature, radiation, and also outer space.
These micro-organisms can survive at an extremely low temperature of 1 K and extremely high temperature of about 420 K.