<span>False. In order to create a control group one must understand the baseline of what is happening. Therefore placebos are given in order to establish this control group. These control groups allow understanding of what an the actual experimental drug, in the case of clinical trials, can do.</span>
Lymphocytes produce antibodies - proteins<span> that recognize foreign substances and attach themselves to them.</span>
S-shaped growth curve(sigmoid growth curve) A pattern of growth in which, in a new environment, the population density of an organism increases slowly initially, in a positive acceleration phase; then increases rapidly, approaching an exponential growth rate as in the J-shaped curve.