What are 3 reasons that natural selection occurs

The adaptive immune response, or third line of defense, is activated when the first and second lines of defense do not succeed in containing an infection.

Which of the following is not an advantage of conserving water? Select one: a. Ensuring that we have enough clean water in the future Incorrect b. Keeping the costs of water down c.

How many nucleotides are needed to code for an amino acid

Why are plants unable to grow at the bottom of lakes? a. The water is colder at the bottom. b. Sunlight does not reach the bottom. c. Groundwater feeds into the bottom. d. Less fresh water is found at the bottom.

What is the major cause of the greenhouse effect? view available hint (s) what is the major cause of the greenhouse effect?

Which choice is a biotic factor of an ecosystem soil air ants sun

Which of the following are necessary for a seed to germinate? 1. moisture content of seed must be at least 9% 2. Moisture content of the seed must be less than 9% 3. certain enzymes in the seed are activated 4. temperature must be above 80 degrees 5.

Give 2 possible circumstances or actions that may lead to a decrease in the TFR of a population

What's system includes oceans, lakes rivers and groundwater's

What extinction event wiped out the dinosaurs