स्तनधारी के हृदय में निम्नलिखित में से कौन प्राथमिक प्राकृतिक पेसमेकर के रूप में कार्य करता है?

What term describes animals that regulate their body temperature internally through metabolic heat?

In the context of marine and aquatic ecosystems, how is the phenomenon of bioluminescence precisely defined?

The renal portal system is absent in which of the following animal groups?