The correct answers are: sensation; perception.
Answer 1: Detecting the black marks on the page relies on the process of sensation.
In psychology, sensation refers to the process by which animals and humans detect external stimuli such as sound, light, heat, pressure etc., through their senses (sight, sound, touch, etc.). In this instance, when you detect black marks on a page, you are doing so through the process of sensation- where your eyes detect the visual stimuli on the page.
Answer 2: The ability to interpret these black lines and curves as letters and words involves the process of perception.
Perception refers to the mental process by which we make sense of or interpret sensations or sensory stimuli. In this instance, when you interpret the black lines and curves you see on the page as letters and words, you are doing so by using your cognitive perception ability- where you make sense of the lines and curves and interpret them as text.