Pl help Scientists track a flock of for three years to learn their
migratory patterns.
Is it a experiment or a Observational Study?

Describe the two types of vascular tissue

Which one is an advantage of external fertilization a. the offspring are genetically identical to the parents b. more eggs can be fertilzed at one time c. more sperm can be released at one time d. more protection is available for developing plz

Which nutrient tends to cycle within a single ecosystem?