Problem: Bird migration routes have been studied by a variety of techniques including the oldest, marking. Swans have been marked with a nick on the beak since about 1560 in England. Scientific ringing was pioneered by Hans Christian Cornelius Mortensen in 1899. Other techniques include radar and satellite tracking.
What are other forms of studying migration?
The answer is the following: radar and satellite tracking

Problem: Puberty occurs through a long process and begins with a surge in hormone production, which in turn causes a number of physical changes. It is the stage of life characterized by the appearance and development of secondary sex characteristics (for example, a deeper voice and larger adam's apple in boys, and development of breasts and more curved and prominent hips in girls) and a strong shift in hormonal balance towards an adult state. This is triggered by the pituitary gland, which secretes a surge of hormonal agents into the blood stream, initiating a chain reaction to occur. The male and female gonads are subsequently activated, which puts them into a state of rapid growth and development; the triggered gonads now commence the mass production of the necessary chemicals. The testes primarily release testosterone, and the ovaries predominantly dispense estrogen. The production of these hormones increases gradually until sexual maturation is met. Some boys may develop gynecomastia due to an imbalance of sex hormones, tissue responsiveness or obesity.
Which part of the body releases testosterone in males?
The answer is the following: testes

Problem: Currently, international agreements are executed by executive agreement rather than treaties at a rate of 10:1. Despite the relative ease of executive agreements, the President still often chooses to pursue the formal treaty process over an executive agreement in order to gain congressional support on matters that require the Congress to pass implementing legislation or appropriate funds, and those agreements that impose long-term, complex legal obligations on the United States. For example, the deal by the United States, Iran and other countries is not a Treaty.
The president of the United States might prefer the formal treaty process for agreements that impose what type of legal obligations on the US?
The answer is the following: long-term, complex

Problem: While pursuing his PhD at Princeton, Feynman married his high school sweetheart, Arline Greenbaum (often misspelled "Arlene"), despite the knowledge that she was seriously ill with tuberculosisan incurable disease at the time. She died in 1945. In 1946, Feynman wrote a letter to her, expressing his deep love and heartbreak, that he kept for the rest of his life. ("Please excuse my not mailing this," the letter concluded, "but I don't know your new address.") This portion of Feynman's life was portrayed in the 1996 film Infinity, which featured Feynman's daughter, Michelle, in a cameo role.
Who played a cameo in a film about Feynman?
The answer is the following:
Feynman's daughter, Michelle