If those are the only answers i would say mutualism
<span>Infection is the term used to describe the process through microorganisms that cause diseases. The invasion of a host by a pathogenic microorganism multiplies in the tissues and the reaction of the host to its presence and to its possible toxins and can be caused by bacteria, fungi, viruses, protozoa or prions.</span>
There should be options for this question. I manged to find them elsewhere. They are:
A) the period during which tremendous growth occurs and the organs continue to develop and become functional
B) the period during which the umbilical cord develops
C) the period during which the major organs and structures of the organism first develop
D) the period during which the zygote moves down to the uterus and begins to implant in the lining
The correct answer is C. The embryonic period is the period during which the major organs and structures of the organism first develop. The embryonic period lasts from implantation of the egg in the uterus until about 8 weeks from the time of conception. It is the second major stage of prenatal development, prior to embryonic is the germinal stage and lastly is the fetal stage.