Why do only certain organs called the target organs respond to the presence of a specific hormone?

What is the main function of respiratory systems in animals?

A closed circulatory system:

When tissue is torn or injured, a chemical is released. This chemical causes platelets in the blood to activate. Once these platelets have activated, they release a chemical which signals more platelets to activate, until the wound is clotted. This is an example of:

Some plants have special root structures for close association with bacteria. This allows them to:

What is the main function of respiratory systems in animals?

Which of the following molecules are broken down in the stomach?

Which of the following is true about light-independent reactions? Mark all that apply

Which of the following is true about light-independent reactions? Mark all that apply

Which of the following is a prediction for the following study: Male birds are usually more colorful than females. An experiment will paint males to be drab and look at how attractive they are to females.