How can seals survive in a polar climate where the temperature prevails below $0^{\circ} C$?

Community is a group of independent and interacting population of

Crop plants grown in monoculture are

Consider the following four statements regarding certain desert animals like the kangaroo rat:
$(a)$ They have a dark color,a high rate of reproduction,and excrete solid urine.
$(b)$ They do not drink water,breathe slowly to conserve water,and their body is covered by thick hair.
$(c)$ They use dry seeds as food and do not require drinking water.
$(d)$ They excrete very concentrated urine and do not use water to regulate body temperature.
Which two of the above statements are true for such animals?

Eurythermal animals and plants are those which

In the ecological hierarchy,the basic unit is . . . . . . .