How many types of organisms are there on Earth?

tens

thousands

millions

hundreds

1. The situation in which alle frequencies in the gene pool of a population remain constant is called (a) evolution (b) genetic drift (c) genetic equilibirium (d) natural selection 2.

What limits the species of plants that can grow in an area?

Which type of reproduction involves only one parent?

Some snake embryos have small buds resembling limbs. These buds disappear at later stages of embryo development. These findings suggest that these snakes

In which of the following patterns of disease does the patient experience no signs or symptoms? A) decline B) prodromal C) convalescence D) incubation E) incubation and convalescence

Make a claim that answers the scientific question

A cow eating grass is an example of A) herbivory B) predation C) habitat destruction D) a keystone species

Macrophages as a means of cancer treatment? Does it actually work? Has it been tested on people?

Which of the following is NOT necessary for respiration? A) quinones B) cytochromes C) a source of electrons D) flavoproteins E) oxygen

What moderates weather so that highs and lows are less extreme?