Viruses are not always classified as living cells because they cannot live independently. They rely on a host to provide all resources to live, without a host they are in a dormant, near dead like state. Therefore it has to define a virus as dead or alive as it may or may not have a host.
Answer:
Birds require high levels of oxygen and, therefore, high rates of gas exchange due to flight demands. Avian resting oxygen consumption is high compared to that of mammals and other vertebrates, and this increases even more during the flight.
Explanation:
Compared to mammals, birds have specific adaptations of the respiratory system that result in higher levels of oxygen exchange.
D ribosomes because it makes the energy for the cells
Answer:
Unisexual and bisexual organisms are differentiated based on the reproductive systems they posses. Unisexual organisms have separate sexes male or female. Male and female reproductive systems are present in different individuals hence unisexual organisms produce male or female gametes but never both. Bisexual organisms have both male and female reproductive systems within the same individual. Hence, they are capable of producing both types of gametes. Some flowers are unisexual, and they possess only pistils or stamens. Some flowers are bisexual, and they possess both stamens and pistils together. This is the difference between unisexual and bisexual organisms.
Answer:
A scientific hypothesis can become a theory if the hypothesis is tested extensively and competing hypotheses are eliminated.
Explanation:
So yeah if you have a lot of evidence and it is tested mutiple times it consider a theory.