<h2>540 million years ago
</h2>
Paleozoic.
Era immediately follows Precambrian It lasted about 4.5 billion years.
When did abundant fossil evidence first appear in the geologic record.
540 million years ago.
Answer:
Jennifer should understand that exposure to teratogens can cause the most damage during exposures such as <em>the duration of exposure, the amount of teratogenic substance, and the stage of development the embryo or fetus is in during the exposure. </em>
Explanation:
<em>Teratogens</em> may affect the embryo or fetus in a number of ways, causing physical malformations, problems in the behavioral or emotional development of the child, and decreased intellectual quotient (IQ) in the child. Additionally, <em>teratogens</em> may also affect pregnancies and cause complications such as preterm labors, spontaneous abortions, or miscarriages. <em>Teratogens </em>are classified into four types: physical agents, metabolic conditions, infection, and finally, drugs and chemicals.
Answer:
Parasitism describes a relationship between two organisms where one gets benefit and other get harm.
Explanation:
Parasitism is a type of symbiotic association that is present between two different organisms. In association, one organism gets benefit from the other and the other is damaged. For example, association between mosquitoes and human is parasitism because mosquitoes get benefit in the form of food while human is damaged due to disease cause by mosquito biting.
<span>When practicing birth control as natural family planning, it is not true that it is almost 100 percent effective. Birth control as natural family planning does require careful tracking of the menstrual cycle, demands focus on bodily changes, and does require women from having sex on days ovulating and following. Even if sex is is had outside ovulating days, it is possible to get pregnant, thus it is not 100 percent effective.</span>
<span>Carbon-based macromolecules are found in all life forms.</span>
