Answer:
ecosystems are a topic in a biology courses
All the cells in a person's body have the same DNA and the same genes. However, the difference between cells in different tissues and organs is that the "expression" of the genes differs between cells. Expression means that the message from the DNA is being copied and made into protein.
True
All somatic cells have same genes but the genes whose product is not needed are turned off. Some genes are expressed constitutively and some genes are turned off and on depending upon the requirement of proteins.
Persistent chlorinated hydrocarbon pesticides persist in the environment and accumulate in the foods chain causing harmful effects on the environment including posing a threat to humans health in the long term. Nonpersistent organophosphate pesticides are more toxic than the former but degrade after a short life span. Therefore they cause immediate harm in case one is in contact with them.
The fact that they do not accumulate in the environment, they are more favourable than chlorinated hydrocarbon pesticides. Chlorinated hydrocarbon pesticides will affect several generations due to their accumulation in the environment. However they don't need to be re-applied hence are less expensive
Semipermeable means only certain substances can pass through. I imagine you are talking about cell membranes which are semipermeable. This means vital things like oxygen and nutrients are able to pass through the membrane, while not allowing everything to enter the cell
