X-linked recessive traits can occur in both males and females. Since its recessive it needs both XnXn in females to show up but for males who are hemizygous (XY) they only need a defective copy of Xn for the disease to show up thus option 1 is correct.
I have added a helpful illustration below where we are talking about another x-linked recessive condition in humans: hemophilia.
Answer: a small body of matter from outer space that enters the earth's atmosphere, becoming incandescent as a result of friction and appearing as a streak of light.
Electromagnetic radiation is a type of energy that is commonly known as light. Generally speaking, we say that light travels in waves, and all electromagnetic radiation travels at the same speed which is about 3.0 * 108 meters per second through a vacuum.
