Blood is considered to be a tissue and it is part of the circulatory system.
The human circulatory system functions to transport blood and oxygen from the lungs to the various tissues of the body. The heart pumps the blood throughout the body. The lymphatic system is an extension of the human circulatory system that includes cell-mediated and antibody-mediated immune systems.
Think about it. Caves are dark, with little to no light. If there's no light, why would you need to see? There are far more important senses than sight in cases like these. Senses such as smell, hearing, and touch.
Hope that helped.
Bias is when a scientist is inclined to put their own thoughts before their actual results. Therefore, an ethical scientist would not exhibit this trait.
Logic is when a scientist puts critical thinking and the scientific process first. An ethical scientist WOULD exhibit this trait.
Honesty is when a scientist tells the truth, wether or not their results align with their own thoughts/opinions. An ethical scientist WOULD exhibit this trait.
The answer to your question would be "An ethical scientist exhibits Logic and Honesty"