Answer:
a.There are three signaling pathway
1- Reception in which molecule binds to receptor
2- Signal transduction in which activation of intracellular pathway and enzyme occur.
3- Cellular response in which specific response of cell occur according to receptor and ligand.
b. Three types of receptors are
1- autocrine
2- paracrine
3- endocrine.
Explanation:
autocrine receptors are signaling pathway in which cell releases its molecule and bind to its own cell receptor example cancer cells while paracrine in which ligand binds to other nearby cell receptor and it is used during development and in endocrine cell target distinct cell and travel through blood stream like hormones functioning.
Chloroplast helps the plants and makes photosynthesis happen
<span>Blood provides an ideal opportunity for the study of human variation without cultural prejudice. It can be easily classified for many different genetically inherited blood typing systems. Also significant is the fact that we rarely take blood types into consideration in selecting mates. In addition, few people know their own type today and no one did prior to 1900. As a result, differences in blood type frequencies around the world are most likely due to other factors than social discrimination. Contemporary Japan is somewhat of an exception since there are popular Japanese stereotypes about people with different blood types. This could affect choice in marriage partners for some Japanese. </span>All human populations share the same 29 known blood systems, although they differ in the frequencies of specific types. Given the evolutionary closeness of apes and monkeys to our species, it is not surprising that some of them share a number of blood typing systems with us as well. When we donate blood or have surgery, a small sample is usually taken in advance for at least ABO and Rh systems typing. If you are O+, the O is your ABO type and the + is your Rh type. It is possible to be A, B, AB, or O as well as Rh+ or Rh- You inherited your blood types from your parents and the environment in which you live cannot change them. I took it from a website: http://anthro.palomar.edu/vary/vary_3.htm
They r able to dig down by eating soil, then eliminating them through the anus
their digestive system is able to break down decomposing plants, that is a common source of organic materials in the soil
