Which of statements is/are true for sexual reproduction in plants?

1. plants are obtained from seeds

2. two plants are always essential

3. only insects are agents of pollination

4. Fertilization can occur only after pollination

Which concept explains why DNA is not always identical in cells after mitosis?

Cody notices that if he stirs his hot oatmeal quickly, two things happen: Much more steam rises from his oatmeal than when he does not stir it. His oatmeal cools off much more quickly than when he does not stir it.

Is the paleozoic era is the longest time period in the history of earth?

Which organism is likely to be in the bottom trophic level of a food chain seal algae frill whale?

What is the distance covered by a vehicle moving in a straight line during 20 s if the vehicle changes its speed from 10 m/s to 16 m/s during that time interval?

What happens to the total charge of the compound after the ions bond together?

How many atoms lined up side by side would equal the thickness of a book page?

If an ambulance hits someone on the road while transporting someone to a hospital, do they bring that person with them too?

Cell biologists have introduced radioactively labeled carbohydrates, fats, and amino acids to living cells, allowed time for cell metabolism, and then placed the cells in a blender and separated out the various cell organelles from the cytoplasm.

Increased production of goods makes our lives more comfortable, but causes an increase in the demand for energy and other resources. One negative impact of this situation on ecosystems is an increase in