Answer:
Scientist count the world humans population with an organization called The United Nations Population Division (UNPD),
Explanation:
Which keeps track of the world population, projects that the world's human population will hit 7 billion on Halloween Day 2011. Admittedly, that is just an estimate: There's no way to know exactly how many people are alive at any given moment, and the true date that humanity's ranks will surpass 7 billion could come in the weeks or months before or after Oct. 31. Nonetheless, the UN's guess is the best there is.
Ectothermic animals are cold blooded animals, or fishes, amphibians, reptiles, and invertebrates. So the right answer would be turtles and lizards. If the answer choices was supposed to look like this
turtles and lizards
birds and mammals
frogs and mammals
lizards and birds
It would be the first option.
Hope this helps!
Answer:HIV attacks a specific type of immune system cell in the body. It's known as the CD4 helper cell or T cell. When HIV destroys this cell, it becomes harder for the body to fight off other infections. When HIV is left untreated, even a minor infection such as a cold can be much more severe.
Explanation:
Answer:
Thalidomide may be defined as a type of the sedative drug that in the earlier time referred for the pregnant ladies. This drug causes the world wide tragedy and acts as a teratogen.
This drug causes mutation in the fetus. The Ames test is effective to understand the mutagenicity of the drug. In this test, if the auxotrophic strain of the bacteria is grown on the the deficient media containing thalidomide drug. The bacteria growth indicates the positive Ames test and the substance is considered as mutagen.
